The Doc is in ...
Dwight Gooden has signed a contract to participate in a Celebrity Boxing match on March 7 in Atlantic City, TMZ Sports has learned.
The former MLB star -- who has recently been dealing with substance abuse issues -- has decided that getting physically active again could be the best thing for him ... so he's agreed to box.
54-year-old Gooden has been working with Celebrity Boxing promoter Damon Feldman for months -- in fact, Doc was the guest referee for Dustin Diamond's (Screech) last fight back in Sept.