NFL legend John Madden is recovering after undergoing open heart surgery -- and is "expected to fully recover" ... so says NFL commish Roger Goodell.
The 79-year-old Hall of Fame coach was released from a San Francisco hospital Wednesday -- after docs performed a procedure to repair blockages in his heart.
Goodell spoke with Madden ... and says, "He sounds great, but is frustrated about being on injured reserve for the time being."
"He is anxious to return to action soon doing the important work he does for our game. He’s a tremendous fountain of ideas and we can’t wait to get him back. We are all pleased to know that John’s procedure was successful and wish him a speedy recovery."
Madden still does a lot of work with the NFL -- serving on the NFL Player Safety Advisory Panel and the Coaches Subcommittee to the Competition Committee.