Nobody ever questioned Logan Mankins' toughness before, and after this latest bit of news, nobody ever will.
Mike Reiss of ESPNBoston.com tweeted that Logan Mankins had surgery on a torn ACL after the Super Bowl, and even played on the injury without even knowing he had torn it.
The Patriots signed Robert Gallery to a one-year deal earlier on Monday, and the signing makes even more sense now. Gallery has spent time at both the offensive guard and offensive tackle position during his career, and is not only a serious option to start on the Patriots, but also a safety net in case Mankins can't return to the team in time for the start of the season.
Seeing as Mankins' injury didn't appear in the Patriots' pre-Super Bowl injury reports, you have to assume it happened at some point during the game, although it's unclear when exactly it happened.