| 1956-12-13 | Jackie Robinson | Refused to report to Giants. | 2B-3B | 5-11 | 204 | R | R | 1919-01-31 | Cairo,GA |
| MLB | 1947-1956 | 1947-1956 |
| 1956-12-13 | Jackie Robinson | Traded by Dodgers to Giants for Dick Littlefield and Cash. Trade Voided (January 13,1956) | 2B-3B | 5-11 | 204 | R | R | 1919-01-31 | Cairo,GA |
| MLB | 1947-1956 | 1947-1956 |
| 1956-12-13 | Dick Littlefield | Traded by Dodgers to Giants for Dick Littlefield and Cash. Trade Voided (January 13,1956) | P | 6-0 | 180 | L | L | 1926-03-18 | Detroit,MI |
| MLB | 1950-1958 | 1950-1958 |
| 1956-12-13 | Dick Littlefield | Traded by Giants with Cash to Dodgers for Jackie Robinson. Trade Voided (January 13,1956) | P | 6-0 | 180 | L | L | 1926-03-18 | Detroit,MI |
| MLB | 1950-1958 | 1950-1958 |
| 1956-12-10 | Bobby Bolin | Signed as undrafted amateur Free Agent by Giants. | P | 6-4 | 200 | R | R | 1939-01-29 | Hickory Grove,SC | 1956- 0- 0-NY1
| MLB | 1961-1973 | 1957-1973 |
| 1956-12-03 | Bill Froats | Selected by Giants from Yankees in the minor league draft. | P | 6-0 | 180 | L | L | 1930-10-20 | New York,NY |
| MLB | 1955-1955 | 1955-1955 |
| 1956-12-03 | Roger McCardell | Selected by Giants from Braves in the minor league draft. | C | 6-0 | 200 | R | R | 1932-08-29 | Gorsuch Mills,MD | 1950- 0- 0-BSN
| MLB | 1959-1959 | 1959-1959 |
| 1956-12-03 | Daryl Robertson | Selected by Braves from Giants in the minor league draft. | SS-3B | 6-0 | 184 | R | R | 1936-01-05 | Cripple Creek,CO | 1954- 0- 0-NY1
| MLB | 1962-1962 | 1962-1962 |
| 1956-12-03 | Ed White | Selected by Giants from White Sox in the minor league draft. | OF | 6-2 | 200 | R | R | 1926-04-06 | Anniston,AL |
| MLB | 1955-1955 | 1955-1955 |
| 1956-10-26 | Hank Sauer | Signed as Free Agent by Giants. | OF-1B | 6-4 | 199 | R | R | 1917-03-17 | Pittsburgh,PA |
| MLB | 1941-1959 | 1941-1959 |
| 1956-10-11 | Jim Hearn | Traded by Giants to Phillies for Stu Miller. | P | 6-3 | 205 | R | R | 1921-04-11 | Atlanta,GA |
| MLB | 1947-1959 | 1947-1959 |
| 1956-10-11 | Stu Miller | Traded by Phillies to Giants for Jim Hearn. | P | 5-11 | 165 | R | R | 1927-12-26 | Northampton,MA |
| MLB | 1952-1968 | 1952-1968 |
| 1956-10-01 | Gordon Jones | Traded by Cardinals with Bill Sarni, Red Schoendienst, Jackie Brandt and Dick Littlefield to Giants for Whitey Lockman, Don Liddle, Ray Katt and Alvin Dark. | P | 6-0 | 190 | R | R | 1930-04-02 | Portland,OR |
| MLB | 1954-1965 | 1954-1965 |
| 1956-08-31 | Mike McCormick | Signed as undrafted amateur Free Agent (bonus baby) by Giants. | P | 6-2 | 195 | L | L | 1938-09-29 | Pasadena,CA |
| MLB | 1956-1971 | 1956-1971 |
| 1956-08-22 | George Wilson | Claimed on waivers by Yankees from Giants. | OF-1B | 6-1 | 185 | L | R | 1925-08-30 | Cherryville,NC |
| MLB | 1952-1956 | 1952-1956 |
| 1956-08-20 | Max Surkont | Purchased by Giants from Red Sox. | P | 6-0 | 205 | R | R | 1922-06-16 | Central Falls,RI |
| MLB | 1949-1957 | 1949-1957 |
| 1956-06-14 | Red Schoendienst | Traded by Cardinals with Gordon Jones, Bill Sarni, Jackie Brandt and Dick Littlefield to Giants for Whitey Lockman, Don Liddle, Ray Katt and Alvin Dark. | 2B-OF | 6-0 | 170 | B | R | 1923-02-02 | Germantown,IL |
| MLB | 1945-1963 | 1945-1963 |
| 1956-06-14 | Jackie Brandt | Traded by Cardinals with Gordon Jones, Bill Sarni, Red Schoendienst and Dick Littlefield to Giants for Whitey Lockman, Don Liddle, Ray Katt and Alvin Dark. | OF-3B | 5-11 | 170 | R | R | 1934-04-28 | Omaha,NE |
| MLB | 1956-1967 | 1956-1967 |
| 1956-06-14 | Dick Littlefield | Traded by Cardinals with Gordon Jones, Bill Sarni, Red Schoendienst and Jackie Brandt to Giants for Whitey Lockman, Don Liddle, Ray Katt and Alvin Dark. | P | 6-0 | 180 | L | L | 1926-03-18 | Detroit,MI |
| MLB | 1950-1958 | 1950-1958 |
| 1956-06-14 | Bill Sarni | Traded by Cardinals with Gordon Jones, Red Schoendienst, Jackie Brandt and Dick Littlefield to Giants for Whitey Lockman, Don Liddle, Ray Katt and Alvin Dark. | C | 5-11 | 187 | R | R | 1927-09-19 | Los Angeles,CA |
| MLB | 1951-1956 | 1951-1956 |
| 1956-06-14 | Whitey Lockman | Traded by Giants with Don Liddle, Ray Katt and Alvin Dark to Cardinals for Gordon Jones, Bill Sarni, Red Schoendienst, Jackie Brandt and Dick Littlefield. | 1B-OF | 6-1 | 175 | L | R | 1926-07-25 | Lowell,NC | 1943- 0- 0-NY1
| MLB | 1945-1960 | 1945-1960 |
| 1956-06-14 | Ray Katt | Traded by Giants with Whitey Lockman, Don Liddle and Alvin Dark to Cardinals for Gordon Jones, Bill Sarni, Red Schoendienst, Jackie Brandt and Dick Littlefield. | C | 6-2 | 200 | R | R | 1927-05-09 | New Braunfels,TX |
| MLB | 1952-1959 | 1952-1959 |
| 1956-06-14 | Alvin Dark | Traded by Giants with Whitey Lockman, Don Liddle and Ray Katt to Cardinals for Gordon Jones, Bill Sarni, Red Schoendienst, Jackie Brandt and Dick Littlefield. | SS-3B | 5-11 | 185 | R | R | 1922-01-07 | Comanche,OK |
| MLB | 1946-1960 | 1946-1960 |
| 1956-06-14 | Don Liddle | Traded by Giants with Whitey Lockman, Ray Katt and Alvin Dark to Cardinals for Gordon Jones, Bill Sarni, Red Schoendienst, Jackie Brandt and Dick Littlefield. | P | 5-10 | 165 | L | L | 1925-05-25 | Mount Carmel,IL |
| MLB | 1953-1956 | 1953-1956 |
| 1956-04-21 | Billy Gardner | Purchased by Orioles from Giants. | 2B-SS | 6-0 | 180 | R | R | 1927-07-19 | Waterford,CT |
| MLB | 1954-1963 | 1954-1963 |
| 1956-03-05 | Jim Mangan | Purchased by Giants from Pirates. | C | 5-10 | 190 | R | R | 1929-09-24 | San Francisco,CA |
| MLB | 1952-1956 | 1952-1956 |
| 1956-01-01 | Ernie Bowman | Signed as undrafted amateur Free Agent by Giants. | SS-2B | 5-10 | 160 | R | R | 1935-07-28 | Johnson City,TN | 1956- 0- 0-NY1
| MLB | 1961-1963 | 1961-1963 |
| 1956-01-01 | Neil Wilson | Signed as undrafted amateur Free Agent by Giants. | C | 6-1 | 175 | L | R | 1935-06-14 | Lexington,TN | 1956- 0- 0-NY1
| MLB | 1960-1960 | 1960-1960 |