Ex-NY Yankees pitcher Andy Pettitte has found his second calling -- he's a football coach ... even though he says he doesn't know a helluva lot about the sport.
42-year-old Pettitte retired back in 2013 after 18 seasons in the league ... but Andy tells us he's been keeping busy spending time with his wife and their 4 kids.
One of his post-MLB hobbies ... coaching youth football.
"I don't know a whole lot about football but I'm enjoying it," Pettitte says. "9 and 10 year-old kids, you don't have to teach 'em a whole lot. They have a good time. It's been fun."