I have no idea, but I'm guessing it is someone who logged a lot of games all in one season after being acquired by trade around May and then released at the end of the season. As opposed to a fringe AAAA player who got called up in September a few times but never made the roster out of spring training. Could be an everyday player acquired by trade in May, but maybe the chances of being gone from the Tigers at the end of that season would make it more likely to be a utility player or middle innings relief pitcher? I'll also take a wild guess that it was sometime between 1952-1989, my thinking being that it seems like there were more competing cards companies and specialty cards after that may have snagged a player for a card mid-season. So now I'll go and see if there was a utility infielder who, say, played 80 games for the Tigers in 1977 but never again, maybe even was released late in the season.
Update: 1977 didn't work. So went back to 1976, and found 2B Pedro Garcia who played 77 games for the Tigers after having played 41 games for Milwaukee that season, then played all of 1977 with Toronto. I remember, even though he played so little with the Tigers. I must remember him getting coverage as an inaugural Blue Jay. Hell, I'll go with Pedro Garcia as my answer.
Edit: Damn!