Yes, he was injured, here it is:
1986:
In September 1986, Buckner hit .340 with eight home runs and 22 RBIs, while missing just three games in spite of chronic ankle soreness.
Dave Stapleton should have been on first.
The utility infielder had been a late inning sub for Buckner most of the season.
McNamara still defends his decision to keep Buckner in the game.