Jimmy Uchrinscko James Emerson Uchrinscko (1926-1926)
Bob Uecker Robert George Uecker (1962-1967)
Dan Uggla Daniel Cooley Uggla (2006-2008)
Luis Ugueto Luis Enrique Ugueto (2002-2003)
Frenchy Uhalt Bernard Bartholomew Uhalt (1934-1934)
Bob Uhl Robert Ellwood Uhl (1938-1940)
Ted Uhlaender Theodore Otto Uhlaender (1965-1972)
George Uhle George Ernest Uhle (1919-1936)
Maury Uhler Maurice William Uhler (1914-1914)
Charlie Uhlir Charles Karel Uhlir (1934-1934)
Jerry Ujdur Gerald Raymond Ujdur (1980-1984)
Mike Ulisney Michael Edward Ulisney (1945-1945)
Scott Ullger Scott Matthew Ullger (1983-1983)
Sandy Ullrich Carlos Santiago Ullrich Castello (1944-1945)
Dutch Ulrich Frank W. Ulrich (1925-1927)
Arnold Umbach Arnold William Umbach (1964-1966)
Jim Umbarger James Harold Umbarger (1975-1978)
Jim Umbricht James Umbricht (1959-1963)
Tom Umphlett Thomas Mullen Umphlett (1953-1955)
Willie Underhill Willie Vern Underhill (1927-1928)
Pat Underwood Patrick John Underwood (1979-1983)
Tom Underwood Thomas Gerald Underwood (1974-1984)
Bob Unglaub Robert Alexander Unglaub (1904-1910)
Tim Unroe Timothy Brian Unroe (1995-2000)
Al Unser Albert Bernard Unser (1942-1945)
Del Unser Delbert Bernard Unser (1968-1982)
Woody Upchurch Jefferson Woodrow Upchurch (1935-1936)
Bill Upham William Lawrence Upham (1918-1918)
John Upham John Leslie Upham (1967-1968)
Jerry Upp George Henry Upp (1909-1909)
Dixie Upright Roy T. Upright (1953-1953)
Cecil Upshaw Cecil Lee Upshaw Jr. (1966-1975)
Willie Upshaw Willie Clay Upshaw (1978-1988)
B.J. Upton Melvin Emmanuel Upton (2004-2008)
Bill Upton William Ray Upton (1954-1954)
Justin Upton Justin Irvin Upton. (2007-2008)
Tom Upton Thomas Herbert Upton (1950-1952)
Jack Urban Jack Elmer Urban (1957-1959)
Luke Urban Louis John Urban (1927-1928)
Tom Urbani Thomas James Urbani (1993-1996)
Billy Urbanski William Michael Urbanski (1931-1937)
Ugueth Urbina Ugueth Urtain Urbina (1995-2005)
Lino Urdaneta Lino Urdaneta (2004-2007)
Jose Uribe Jose Alta Uribe (1984-1993)
Juan Uribe Juan C. Tena Uribe (2001-2008)
John Urrea John Goody Urrea (1977-1981)
Lon Ury Louis Newton Ury (1903-1903)
Bob Usher Robert Royce Usher (1946-1957)
Dutch Ussat William August Ussat (1925-1927)
Chase Utley Chase Cameron Utley (2003-2008)