It was interference.
The Red Sox and Reds split the first two games of the 1975 World Series.
In Game 3, Boston trailed 5-1 after five innings, but came back, tying the game 5-5 in the top of the ninth on Dwight Evans's two-run homer. In the home half of the tenth, Cesar Geronimo led off with a single to right off Jim Willoughby.
Ed Armbrister, batting for the pitcher, attempted to bunt. The ball bounced high in front of the plate. Armbrister froze, then took a step or two before Red Sox catcher Carlton Fisk bumped into him.