Getty Images says:
First baseman Keith Hernandez #17 of the New York Mets takes the throw over at first base against the Chicago Cubs during a Major League Baseball game circa 1986 at Wrigley Field in Chicago, Illinois. Hernandez played for the Mets from 1983-89.
Yep, that’s clearly Keith Hernandez. And, in fact, we know this is 1986 for sure. Why? Because Hernandez is wearing a patch on his left sleeve. The patch is for the 25th season of the Mets — not their 25th anniversary, that would have been 1987. Anyway, that’s the only possible year for that uniform, the Mets otherwise did not wear any such sleeve patch between 1976 and 1994.