Willie Stargell was the starter and Bob Robertson was the backup.
Mario Mendoza played in just one game at third base for the Pittsburgh Pirates in 1975 and did not start. He played for a total of 7 outs, equivalent to .26 9-inning games. He made no putouts, had no assists, and committed no errors, equivalent to 0 errors per 9-inning game. He had no double plays.
Willie Randolph played in just one game at third base for the Pittsburgh Pirates in 1975 and started. He played for a total of 24 outs, equivalent to .89 9-inning games. He made no putouts, had 3 assists, and committed 3 errors, equivalent to 3.375 errors per 9-inning game. He had no double plays.
Ed Kirkpatrick played in 28 games at first base for the Pittsburgh Pirates in 1975, starting in 11 of them. He played for a total of 404 outs, equivalent to 14.96 9-inning games. He made 141 putouts, had 9 assists, and committed no errors, equivalent to 0 errors per 9-inning game. He had 10 double plays.
Al Oliver played in 4 games at first base for the Pittsburgh Pirates in 1975, starting in 3 of them. He played for a total of 72 outs, equivalent to 2.67 9-inning games. He made 29 putouts, had one assist, and committed no errors, equivalent to 0 errors per 9-inning game. He had 3 double plays.
Bob Robertson played in 27 games at first base for the Pittsburgh Pirates in 1975, starting in 25 of them. He played for a total of 620 outs, equivalent to 22.96 9-inning games. He made 209 putouts, had 18 assists, and committed one error, equivalent to .044 errors per 9-inning game. He had 10 double plays.
Willie Stargell played in 122 games at first base for the Pittsburgh Pirates in 1975, starting in all of them. He played for a total of 3216 outs, equivalent to 119.11 9-inning games. He made 1121 putouts, had 54 assists, and committed 10 errors, equivalent to .084 errors per 9-inning game. He had 112 double plays.
Paul Popovich played in 8 games at second base for the Pittsburgh Pirates in 1975, starting in 5 of them. He played for a total of 171 outs, equivalent to 6.33 9-inning games. He made 16 putouts, had 14 assists, and committed no errors, equivalent to 0 errors per 9-inning game. He had 2 double plays.
Willie Randolph played in 14 games at second base for the Pittsburgh Pirates in 1975, starting in 12 of them. He played for a total of 343 outs, equivalent to 12.7 9-inning games. He made 34 putouts, had 42 assists, and committed 3 errors, equivalent to .236 errors per 9-inning game. He had 8 double plays.
Rennie Stennett played in 144 games at second base for the Pittsburgh Pirates in 1975, starting in all of them. He played for a total of 3798 outs, equivalent to 140.67 9-inning games. He made 379 putouts, had 463 assists, and committed 18 errors, equivalent to .128 errors per 9-inning game. He had 98 double plays.
Richie Hebner played in 126 games at third base for the Pittsburgh Pirates in 1975, starting in 124 of them. He played for a total of 3253 outs, equivalent to 120.48 9-inning games. He made 86 putouts, had 244 assists, and committed 19 errors, equivalent to .158 errors per 9-inning game. He had 17 double plays.
Art Howe played in 42 games at third base for the Pittsburgh Pirates in 1975, starting in 36 of them. He played for a total of 1028 outs, equivalent to 38.07 9-inning games. He made 17 putouts, had 89 assists, and committed 7 errors, equivalent to .184 errors per 9-inning game. He had 4 double plays.
Richie Hebner was the starter and Jose Pagan was the backup.