John David Geisel (born January 18, 1955) is an American former professional baseball pitcher.

He played in Major League Baseball (MLB) for the Chicago Cubs, Toronto Blue Jays, and Seattle Mariners.

Geisel made his major league debut with the Cubs on June 13, 1978, at Riverfront Stadium, pitching one relief inning against the Reds without allowing a baserunner.

In the 1983 offseason, Geisel was selected by the Seattle Mariners from Toronto in the 1983 rule 5 draft.

He pitched his final major league game on May 18, 1985, at Seattle's Kingdome in a victory over the visiting Baltimore Orioles.