| Manny Siaca | H | 2008-2008 | Alabama A&M |
| Andrew Siano | OF | 2009-2012 | Hartford, Keystone College |
| Mark Siano | P | 2000-2003 | Princeton |
| Julio Siberio | P | 2003-2006 | Northwestern |
| Matthew Sibigtroth | SS | 2004-2004 | Kishwaukee College, Dayton |
| Cam Sibley | --- | 2020-2020 | Northwestern State |
| Hunter Sibley | P-IF | 2019-2019 | Iona College |
| J.C. Sibley | OF | 2004-2005 | Kansas, Southern Nevada, UNLV |
| Travis Sibley | IF | 2012-2015 | Texas-Arlington |
| Tyler Sibley | IF | 2009-2012 | Texas State |
| Brian Sicher | C | 2012-2014 | Air Force |
| Cole Sichley | P | 2018-2018 | Pennsylvania |
| John Siciliano | IF | 2012-2013 | High Point |
| Matthew Siciliano | P | 2011-2013 | Quinnipiac, St. Mary's College of Maryland |
| Kayle Sickler | P | 2007-2008 | Penn State |
| Tom Sickling | IF | 2011-2011 | Texas-Pan American, South Florida CC |
| Alex Siddle | P | 2013-2016 | SE Missouri State |
| Joey Siddons | IF | 2009-2010 | Cal State Fullerton, Oxnard College |
| Blake Sides | C | 2014-2016 | Eastern Kentucky, Spartanburg Methodist College |
| Julian Sides | P | 2003-2005 | UNC Charlotte |
| Arman Sidhu | 3B | 2003-2006 | Northeastern |
| Chad Sidmore | P | 2001-2004 | Le Moyne |
| Greg Sidor | UT | 2014-2014 | Illinois State |
| Mike Sidoti | C | 2002-2003 | Marist |
| Jake Sidwell | C | 2014-2017 | Davidson College |
| Kirk Sidwell | OF | 2016-2019 | Stetson, Embry-Riddle |
| Chris Siebenaler | P | 2005-2007 | Florida Intl, Polk State |
| Josh Siebenaler | IF-OF | 2008-2009 | Central Florida, Polk State |
| Ben Siegel | OF | 2014-2016 | Florida Atlantic, FSC at jacksonville |
| Josiah Siegel | P | 2020-2020 | Georgia Tech |
| Matt Siegel | COACH | 1998-2001 | Florida |
| Brandon Siegenthaler | P | 2020-2020 | Villanova |
| Joseph Siegfried | P | 2013-2013 | Northwestern State |
| Josh Sieglitz | P | 2017-2019 | Grand Canyon, Gateway CC, Missouri Baptist |
| Brett Siegmund | IF-P | 2007-2007 | Indiana State, Santa Ana College, Vanguard Southern California |
| Chris Siemer | C | 2008-2008 | Missouri State |
| Austin Siener | IF | 2016-2018 | Texas-Pan American, Illinois Central College |
| Steven Siers | P | 2005-2008 | Texas State |
| Chris Siewert | SS | 2006-2007 | Southern Nevada, Tennessee, Nevada |
| Noah Sifrit | P-OF | 2018-2020 | Oklahoma State |
| Dino Sifuentes | C | 2007-2009 | Duquesne |
| Emanuel Sifuentes | IF | 2008-2010 | Pepperdine |
| Calvin Sigelbaum | IF | 2009-2012 | Davidson College |
| Andy Sigerich | P | 2002-2006 | Illinois, Illinois-Chicago |
| AJ Siggers | OF | 2005-2008 | Louisiana-Monroe |
| Matt Siggins | P | 2011-2012 | UMD-Baltimore Cty, Frederick CC |
| Josiah Sightler | P | 2019-2020 | South Carolina |
| Zach Sightler | P | 2013-2016 | Winthrop |
| Nick Sigismondi | P-SS | 2005-2005 | Mount Saint Mary |
| Callaway Sigler | OF | 2019-2020 | James Madison |
| Jermika Sigler | OF | 2006-2008 | Alabama A&M |
| Walker Sigman | P | 2018-2018 | Brigham Young |
| Brian Sigmon | C | 2001-2004 | Western Carolina |
| Marcus Sigmon | IF | 2013-2017 | Troy, Indian River CC, Valdosta State |
| Ryan Sigmon | IF | 2015-2017 | UNC-Greensboro, Danville Area CC |
| Lucas Signor | OF | 2011-2011 | Niagara, Patrick Henry College |
| John Signore | P | 2016-2018 | Fairfield |
| Jay Signorelli | P | 2000-2001 | Manatee-Sarasota, Florida Southern |
| Chris Sigourney | P | 1980-1980 | Illinois |
| Eric Sigovich | P | 2015-2018 | Appalachian State, Saint Joseph's, Pitt CC |
| Jack Sigrist | IF | 2019-2020 | Wichita State |
| Charles Sikes | 1B | 2013-2016 | Savannah State, South Georgia College |
| Corey Sikes | P | 2015-2018 | Western Carolina |
| Graham Sikes | C | 2001-2002 | Liberty |
| Phillip Sikes | CF | 2018-2020 | New Mexico, Pima CC, Texas Christian |
| Kevin Sikora | P | 2007-2010 | Eastern Michigan |
| Easton Sikorski | P | 2019-2020 | Western Michigan |
| Jimmy Sikorski | P | 2012-2014 | Cornell |
| Mark Sikorski | P | 2006-2009 | Canisius College, Niagara |
| Petr Sila | IF | 2014-2015 | Ark-Little Rock, Redlands CC |
| Joey Silan | P | 2019-2020 | Delaware |
| Aaron Silbar | IF | 2011-2014 | Columbia |
| Nick Silber | P | 2017-2018 | Rice |
| Nolan Silberhorn | P | 2015-2018 | Toledo |
| Blake Silguero | OF | 2009-2010 | San Diego State, Cisco Junior College |
| Jake Sillavan | P | 2007-2007 | Texas-San Antonio |
| John Sills | IF | 2007-2010 | Holy Cross |
| Mike Sills | P | 2004-2004 | Florida A&M |
| Noah Sills | P | 2016-2019 | Lamar, Alvin CC |
| Tyler Sills | P | 2019-2020 | Lipscomb |
| Michael Sillyman | 1B | 2013-2014 | Memphis |
| Chase Silseth | P | 2019-2019 | Tennessee |
| Alex Silva | P | 2010-2010 | Texas A&M-Corpus Christi |
| Cameron Silva | C | 2013-2016 | Dayton, Glendale CC CA, Pasadena City College |
| Gray Silva | C | 2003-2004 | Mississippi State |
| Hunter Silva | P | 2011-2012 | Sam Houston State, San Jacinto |
| Jared Silva | P | 2015-2016 | Va Military Inst. |
| Jarron Silva | OF | 2017-2020 | UCLA |
| Jerry Silva | P | 2013-2016 | Chicago State |
| Joe Silva | UT | 2001-2003 | Loyola Marymount, Lynn |
| Kobe Silva | --- | 2020-2020 | Cal State Bakersfield |
| Kyle Silva | OF | 2012-2014 | Maine |
| Ryan Silva | P | 2018-2020 | California Baptist |
| Scott Silva | IF | 2014-2017 | Gonzaga, Fresno City College, Fresno State |
| Sean Silva | P | 2010-2014 | USC, Fresno City College, UNLV |
| Raul Silva-Martinez | C | 2012-2015 | UC Irvine |
| Chase Silvani | OF | 2013-2016 | Jacksonville State |
| Alex Silver | IF | 2011-2014 | Texas |
| Clay Silver | IF | 2003-2004 | Texas-Arlington, Abilene Christian |
| Kyle Silver | IF | 2004-2007 | Duke, UW Milwaukee |
| Landon Silver | OF | 2017-2019 | UC Santa Barbara, Orange Coast College, Lee University |
| Jamie Silverberg | --- | 2020-2020 | SUNY - Albany |
| Alex Silverman | P | 2005-2008 | Brown |
| Cody Silverman | C | 2011-2014 | Saint Joseph's |
| Doug Silverman | C-OF | 2003-2005 | Navy |
| Jake Silverman | IF | 2008-2008 | Cal State Fullerton, Fullerton College |
| Jordan Silverman | P | 2016-2019 | Rider |
| Mike Silverman | IF | 2003-2005 | Temple |
| Perry Silverman | OF | 2007-2010 | Canisius College |
| Yale Silverman | P | 2004-2006 | Ohio |
| Hunter Silvernail | C | 2018-2019 | Lafayette College |
| Trey Silvers | IF | 2014-2017 | Lamar, Temple College |
| Ari Silverstein | P | 2019-2020 | Delaware, Old Dominion |
| Ethan Silverstein | P | 2004-2007 | Brown |
| Jake Silverstein | OF | 2019-2020 | Dayton |
| Miles Silverstein | IF | 2009-2012 | Pepperdine |
| Spencer Silverstein | 3B | 2006-2007 | Columbia |
| Steve Silverstein | C | 2001-2004 | Quinnipiac, Fairleigh Dickinson |
| Mark Silverthorn | OF-1B | 2001-2003 | Arkansas State |
| Dom Silvestri | P | 2009-2012 | Butler |
| Joe Silvestri | IF | 2007-2007 | Georgetown |
| Josh Silvestri | P | 2017-2017 | James Madison, Harford CC |
| Mark Silvestri | P | 2016-2019 | Rhode Island |
| Stephen Silvestri | P | 2012-2015 | Pennsylvania |
| Joe Silvestrone | C | 2016-2019 | Wagner |
| Kevin Silvett | C | 2008-2008 | San Diego State, Cal State San Marcos |
| Keith Simard | P-OF | 2004-2006 | Holy Cross |
| Kohl Simas | P | 2020-2020 | San Diego |
| Colton Simbeck | OF | 2012-2015 | Memphis, Alabama-Huntsville |
| Dylan Simcik | P | 2016-2017 | Rider |
| Eric Simcox | H | 2007-2007 | Western Michigan |
| Chad Simendinger | P | 2008-2011 | Saint Joseph's |
| Joe Simeone | P | 2018-2020 | Connecticut |
| Hayden Simerly | OF | 2012-2015 | Sam Houston State |
| Jackson Simerly | P | 1999-2002 | East Tennessee State |
| Miles Simington | --- | 2020-2020 | Purdue |
| Tommy Simis | IF | 2009-2013 | Cal State Northridge |
| Blake Simkins | SS-OF | 2004-2004 | Southern Utah |
| Russ Simmerman | IF | 2000-2003 | UNC Wilmington |
| Adam Simmons | P | 2011-2011 | Florida State, South Florida CC |
| Alvin Simmons | OF | 2009-2010 | Grambling State |
| Blake Simmons | IF | 2018-2018 | Georgia Southern |
| Bobby Simmons | P-IF | 2008-2008 | Dayton |
| Brad Simmons | C | 2006-2009 | Jacksonville |
| Brad Simmons | 1B | 2001-2002 | SE Missouri State, Southwestern College |
| Brian Simmons | IF | 2010-2011 | Manhattan College |
| Byron Simmons | H | 2005-2005 | Prairie View A&M |
| Clay Simmons | IF-OF | 2015-2017 | South Florida |
| Cullen Simmons | C | 2000-2002 | Louisiana Tech |
| David Simmons | H | 2006-2008 | Grambling State |
| David Simmons | OF | 2011-2014 | Western Kentucky |
| Derek Simmons | 2B-3B | 2008-2009 | Georgia State, Montevallo |
| Derron Simmons | IF | 2014-2014 | Alabama State |
| Doug Simmons | OF-1B | 2008-2011 | Rice |
| Garett Simmons | P | 2017-2019 | University at Buffalo, Ball State |
| Hunter Simmons | IF | 2014-2017 | Utah |
| Jakai Simmons | OF | 2010-2010 | Maryland-Eastern Shore |
| Jesse Simmons | OF | 2013-2015 | Campbell |
| Kell Simmons | P | 2010-2011 | Prairie View A&M |
| Kyle Simmons | OF | 2014-2015 | Furman |
| Lance Simmons | OF | 2016-2017 | Texas Southern |
| Logan Simmons | P | 2008-2009 | Belmont, Carson-Newman |
| Luke Simmons | 3B | 1999-2002 | Illinois |
| Mathias Simmons | P | 2010-2011 | Northwestern State, Neosho County CC. |
| Matt Simmons | IF | 2014-2017 | Gardner-Webb |
| Nathan Simmons | P | 2014-2016 | St. Mary's (CA), Diablo Valley |
| Nick Simmons | IF-P | 2003-2006 | Western Illinois |
| Nick Simmons | IF | 2017-2019 | Utah Valley U, Diablo Valley |
| O.J. Simmons | OF | 2009-2012 | Grambling State |
| Stan Simmons | OF | 2011-2014 | Long Island-Brooklyn, William Penn University |
| Stone Simmons | --- | 2020-2020 | Furman |
| Darien Simms | OF | 2016-2019 | Arkansas, Sam Houston State |
| Jason Simms | P | 2012-2014 | Sam Houston State, Blinn College |
| Josh Simms | OF | 2009-2012 | Pacific |
| kevin Simms | OF | 2010-2010 | Wright State |
| Khie Simms | OF | 2018-2020 | Norfolk State |
| Trey Simms | OF | 2002-2002 | New Mexico State, Barton County CC |
| Jordan Simo | P | 2004-2005 | St. Mary's (CA), East Los Angeles College |
| Todd Simo | P | 2002-2002 | George Mason, Kean |
| Tim Simoes | IF | 2018-2019 | Army |
| Brandon Simon | C | 2011-2011 | New Orleans, Southwest Mississippi CC |
| Brandon Simon | OF | 2019-2019 | Arkansas-Pine Bluff |
| Brett Simon | C | 2016-2019 | La Salle |
| Brock Simon | P-OF | 2009-2013 | Western Illinois, College of Lake County, William Penn University |
| Brock Simon | P | 2010-2012 | Santa Clara |
| Bryan Simon | H | 2006-2007 | Bowling Green State |
| Bryce Simon | --- | 2020-2020 | Morehead State |
| Christian Simon | P | 2018-2019 | Marshall, Montevallo |
| Cody Simon | 1B-OF | 2012-2015 | Wright State |
| Colt Simon | P | 2007-2007 | Texas-Arlington, Howard College |
| Dane Simon | OF | 2018-2020 | Nicholls State |
| Daniel Simon | P | 2009-2010 | New Mexico State, Lassen CC |
| Elijah Simon | 3B | 2017-2018 | Houston Baptist |
| Glen Simon | P | 2003-2006 | Florida State, Louisville |
| Harrison Simon | P | 2015-2017 | San Francisco, LA Mission, Loyola Marymount |
| Jake Simon | C | 2019-2019 | Bethune-Cookman |
| Jason Simon | 3B-1B | 2001-2002 | Northern Iowa, Kirkwood CC |
| Jeremy Simon | C | 2018-2019 | Houston Baptist |
| Josh Simon | C | 2017-2020 | Va. Commonwealth |
| Kip Simon | IF-P | 2004-2005 | Evansville, Trinidad State Junior College |
| Liam Simon | P | 2020-2020 | Notre Dame |
| Max Simon | P | 2006-2006 | Texas A&M, Kansas State |
| Ryan Simon | P | 2006-2006 | Texas-Arlington, Barton County CC |
| Scott Simon | P | 2012-2014 | Washington State |
| Thain Simon | P | 2008-2009 | Santa Clara |
| Trevor Simon | P | 2015-2018 | Ball State |
| Tyler Simon | IF | 2018-2020 | Kennesaw State |
| Frank Simoncelli | P | 2005-2006 | Eastern Illinois |
| Matt Simonds | OF-IF | 2009-2010 | Georgia Tech |
| Alexander Simone | OF | 2013-2013 | West Alabama |
| Bobby Simone | P | 2008-2011 | Akron |
| Joe Simone | OF | 2017-2019 | Rider |
| John Simone | OF | 2005-2009 | Quinnipiac |
| Matt Simone | P-1B | 2007-2010 | Binghamton |
| Matt Simone | C-OF | 2009-2012 | Iona College, C.W. Post Campus/Long Island |
| Chet Simoneaux | P-C | 2012-2014 | Louisiana-Monroe, Wallace CC, SE Louisiana |
| Courtland Simoneaux | IF | 2018-2018 | Southern |
| Thomas Simoneaux | 2B | 2012-2015 | Louisiana-Lafayette, Louisiana Tech |
| Will Simoneit | C | 2017-2020 | Cornell, Wake Forest |
| Anthony Simonelli | P | 2018-2020 | Coastal Carolina, St. Johns River CC, Virginia Tech |
| Matt Simonelli | IF-OF | 2007-2011 | The Citadel |
| Lou Simonetti | IF | 2010-2010 | Siena College, Roanoke College |
| Matt Simonetti | P | 2014-2018 | Manhattan College |
| Nick Simonian | P | 2016-2018 | Illinois-Chicago, De Anza College |
| KC Simonich | IF-OF | 2018-2020 | Texas Tech, Northwest Florida State College, New Orleans |
| Mike Simonini | IF | 2013-2014 | San Jose State |
| Evan Simonitsch | OF | 2009-2011 | Loyola Marymount |
| CJ Simons | OF | 2005-2006 | Rhode Island |
| Jordan Simons | P | 2013-2013 | Louisville |
| Dan Simonsen | P | 2002-2003 | Utah |
| Jack Simonsen | C | 2018-2020 | North Dakota State |
| Nikolai Simonsen | IF | 2011-2012 | Navy |
| Al Simontis | P | 2002-2004 | Mississippi, Indian River CC, Florida Southern |
| Kris Simonton | IF | 2013-2016 | Akron, Michigan State |
| Russ Simonton | H-P | 2002-2002 | Alcorn State |
| Grant Simotes | IF | 2007-2011 | Western Michigan |
| Mac Simotes | IF | 2011-2011 | Michigan |
| Joe Simourian | OF | 2019-2019 | Navy |
| John Simourian | C | 2017-2020 | Georgetown |
| Derek Simper | 3B | 2003-2003 | San Diego, San Francisco State, Palomar College |
| Chris Simpkins | P | 2007-2010 | Army |
| David Simpkins | P | 2002-2002 | Jacksonville |
| Ryan Simpler | P | 2015-2018 | East Tennessee State |
| Aaron Simpson | OF | 2017-2020 | San Diego, Cypress College, Ball State |
| Ali Simpson | P | 2009-2013 | Bethune-Cookman |
| Bill Simpson | P-IF | 2004-2007 | George Washington, South Carolina |
| Brian Simpson | P | 2004-2004 | Nevada |
| Chandler Simpson | --- | 2020-2020 | Alabama-Birmingham |
| Cody Simpson | P | 2011-2011 | Miss. Valley St |
| Cole Simpson | P-OF | 2019-2020 | The Citadel |
| Eric Simpson | C | 2005-2007 | Quinnipiac |
| Gabe Simpson | IF | 2018-2018 | Maryland-Eastern Shore |
| Jack Simpson | P | 2017-2019 | Bucknell |
| Jeff Simpson | OF | 2008-2011 | Stetson |
| Jordan Simpson | SS | 2013-2016 | Furman |
| Josh Simpson | P | 2013-2016 | Wofford |
| Kyle Simpson | P | 2008-2009 | USC-Upstate |
| Landon Simpson | P | 2013-2016 | Arkansas, Southern Arkansas |
| Luke Simpson | P | 2014-2017 | Longwood |
| Luke Simpson | IF | 2018-2018 | Alabama A&M |
| Marcus Simpson | P | 2004-2004 | Texas Tech, Seward County CC |
| Matt Simpson | C | 1997-1998 | Texas, Fullerton College |
| Max Simpson | P | 2015-2019 | Oklahoma State, Hutchinson CC, Carson-Newman, Emporia State |
| Phil Simpson | P | 2016-2019 | Campbell, Brunswick CC |
| Preston Simpson | IF | 2008-2008 | Presbyterian College |
| Reid Simpson | OF | 2005-2005 | Northwestern, Southwestern |
| Rudy Simpson | OF | 2000-2003 | Cal State Northridge, Riverside CC, Cal State Fullerton |
| Ryne Simpson | P | 2006-2009 | Tennessee |
| Tim Simpson | P | 2010-2012 | Michigan State, Grand Rapids CC, College of the Desert |
| Trent Simpson | P-1B | 2017-2018 | Jacksonville State |
| Tyson Simpson | IF-OF | 2011-2014 | North Carolina Central |
| Will Simpson | 1B | 2020-2020 | Washington |
| Zach Simpson | 2B | 2002-2004 | Vanderbilt |
| Cameron Sims | P | 2013-2016 | Florida A&M |
| Davis Sims | IF | 2017-2020 | Murray State, Western Kentucky |
| Dawson Sims | P | 2019-2019 | Va. Commonwealth, Carson-Newman |
| Donovin Sims | P | 2015-2018 | Northern Illinois |
| Drew Sims | C | 2018-2019 | Utah Valley U |
| J Sims | H | 2007-2007 | Texas Southern |
| Kirk Sims | C | 2010-2011 | The Citadel |
| Landon Sims | --- | 2020-2020 | Mississippi State |
| Larry Sims | OF | 2018-2019 | Arkansas-Pine Bluff |
| Matt Sims | P | 2002-2002 | Mercer |
| Michael Sims | C-IF | 2010-2011 | Longwood |
| Michael Sims | C | 2016-2016 | Va Military Inst. |
| Nick Sims | --- | 2020-2020 | Utah Valley U |
| Tim Simundza | P | 2003-2005 | Evansville |
| Nicholas Sinacola | P | 2019-2020 | Maine |
| Billy Sinacori | IF | 2004-2007 | Sacramento State |
| Greg Sinacori | P | 2010-2010 | New York Tech |
| Jimmy Sinatro | C | 2013-2015 | Gonzaga |
| Matt Sinatro | UT | 2014-2017 | San Francisco |
| Chris Sinclair | C | 2009-2012 | Louisiana-Monroe, Western Nevada CC, Louisiana-Lafayette |
| Connor Sinclair | P | 2011-2012 | Lipscomb, Butler CC |
| Jack Sinclair | P | 2018-2020 | Central Florida |
| Jay Sinclair | 1B | 2008-2008 | Elon |
| Ross Sinclair | OF | 2006-2007 | Creighton, Iowa Western CC |
| Ryan Sinclair | C | 2006-2009 | Stephen F. Austin |
| Zak Sinclair | P | 2009-2009 | NC State |
| Todd Singelyn | P | 1994-1994 | Arizona, Cal State Fullerton |
| Ben Singer | P | 2011-2014 | Bowling Green State |
| Jake Singer | 2B | 2016-2019 | Notre Dame |
| Matt Singer | P | 2007-2010 | Seton Hall |
| Stephen Singer | P | 2007-2010 | UNLV |
| Reid Singewald | OF | 2019-2020 | North Alabama |
| Elliot Singletary | IF | 2004-2005 | Maryland, South Florida CC |
| Kevin Singletary | OF-P | 2013-2013 | Florida A&M |
| Khyle Singleton | P | 2008-2012 | Arkansas-Pine Bluff, Sam Houston State |
| Louis Singleton | P | 2011-2011 | Old Dominion |
| Cole Singsank | --- | 2020-2020 | High Point |
| Tanner Sinicki | P | 2019-2019 | Binghamton |
| Sean Sinisko | P | 2020-2020 | Illinois State |
| Travis Sink | P | 2007-2007 | North Florida |
| Sam Sinkavich | P | 2003-2004 | Cornell, College of San Mateo |
| Jeff Sinkiewicz | P | 2006-2009 | Butler |
| Brooks Sinnen | IF | 2005-2007 | Old Dominion |
| Kurt Sinnen | C-1B | 2014-2017 | Old Dominion |
| Sam Sinnen | P | 2014-2017 | Old Dominion |
| Chris Sinner | OF | 2003-2004 | Gonzaga, Orange Coast College |
| Brian Sinnette | P | 2008-2011 | Grambling State |
| Michael Sinnott | P | 2014-2018 | New York Tech |
| Joe Sinopoli | P | 2010-2012 | Cornell |
| Dalton Sinquefield | OF | 2017-2020 | Troy, Wallace State CC |
| Chris Sintetos | OF | 2009-2012 | Holy Cross |
| Blake Sipe | OF | 2011-2014 | Radford |
| Brian Sipe | C | 2011-2014 | SIU-Edwardsville |
| Zach Sipe | P | 2009-2012 | Navy |
| Kris Sipes | P | 2009-2012 | Morehead State, Bellarmine |
| Julian Sipiora | C | 2011-2012 | Illinois State |
| Aaron Siple | OF | 2014-2015 | New Mexico, Gateway CC |
| Andrew Sipowicz | P-1B | 2016-2019 | Canisius College |
| Chris Sipp | SS-2B | 2004-2007 | Stony Brook |
| Ryan Sipp | P | 2006-2006 | Louisiana-Monroe, Odessa |
| Gerry Siracusa | P-OF | 2019-2020 | Massachusetts-Lowell |
| Jake Siracusa | OF | 2018-2020 | Central Ct State |
| Shane Sirdashney | OF | 2019-2019 | Texas-San Antonio |
| Brendan Siriani | C | 2018-2019 | Army |
| Mike Sirianni | IF | 2002-2005 | Creighton |
| Joe Siringo | P | 2014-2015 | Villanova, Sacred Heart |
| Pat Sirois | OF | 2014-2017 | Central Ct State, Eastern Connecticut State |
| Rich Sirois | P | 2004-2007 | Connecticut |
| Danny Sirven | P | 2017-2019 | Tennessee, Chattanooga State Technical CC, Tampa |
| Fred Sisco | P | 2020-2020 | Campbell |
| Jonathan Sisco | P-IF | 2012-2014 | Middle Tenn State, Volunteer State CC, Wallace State CC |
| Adam Sisk | OF | 2015-2018 | James Madison |
| Chris Sisk | 1B | 2007-2008 | Tennessee-Martin |
| Jackson Sisk | IF | 2019-2020 | Georgia State |
| Matt Sisk | 3B | 2001-2004 | Texas-Pan American, New Mexico |
| Pat Sisk | 3B | 2018-2019 | Furman, South Mountain CC |
| Zach Sisko | IF | 2001-2004 | Notre Dame |
| Brian Sisler | IF | 2013-2016 | Northern Illinois |
| Kyle Sisney | SS-2B | 2008-2008 | Wichita State |
| Brian Sisson | --- | 2018-2018 | Virginia Tech |
| Henry Sisson | P | 2012-2014 | Davidson College, North Carolina |
| Scott Sistilli | P | 2004-2004 | Cal State Northridge, Los Angeles Pierce College |
| Dan Sisto | IF | 2009-2010 | Le Moyne |
| Ricky Sisto | IF | 2018-2019 | Miami, SUNY-Cortland |
| Austin Sistrunk | IF | 2013-2017 | Lipscomb, Middle Tenn State |
| Jon Sistrunk | P-OF | 2005-2005 | Stetson |
| Peter Sitaras | OF | 2014-2017 | Saint Joseph's |
| Pat Sitkins | P | 2001-2004 | Jacksonville |
| Anthony Sitko | P | 2017-2017 | SIU-Edwardsville |
| Ryan Sittauer | OF | 2002-2003 | San Francisco |
| Connor Sitz | P | 2013-2016 | Ohio |
| Matthew Siverling | P | 2020-2020 | Virginia Tech |
| Jordan Sivertsen | OF | 2009-2012 | Southern Illinois |
| Ashton Sivigliano | P | 2013-2014 | Northwestern State, Barton College, West Texas A&M |
| Sam Sivilotti | OF | 2008-2011 | UW Milwaukee |
| Austen Siwiec | P | 2007-2010 | Valparaiso |
| Donnie Sixt | P | 2007-2007 | Indiana U.-Purdue U.-FW, Wabash Valley College |
| Brian Sizemore | P | 2005-2009 | New Mexico State, Northern Colorado |
| Darren Sizemore | P | 2006-2007 | Georgetown, Ohio State |
| Justin Sizemore | 1B | 2010-2013 | Liberty |
| Shawn Sizemore | P-OF | 2010-2013 | Old Dominion |
| Warren Sizemore | P | 2003-2006 | Georgetown |
| Zach Sizemore | IF | 2011-2011 | Butler, West Virginia U. Institute of Technology |
| 376 record(s) |