There's no telling how it happened but, presumably, it occurred during the hectic nature of the Patriots celebration, an overtime victory that had a wild finish.
During the locker room session following the game, intrepid NFL.com reporter Dan Hanzus followed Robert Kraft as the Patriots owner handed out cigars to his players.
Kraft made a special trip over to see his quarterback and when he got there, Brady, after getting a couple of kisses on his cheeks from the owner, informed him that he no longer had his game jersey from Super Bowl LI.
"Somebody stole my game jersey," Brady said.
He then pointed where it was and said, "Yeah, right over there" appearing to wonder how someone just walked out of the locker room with it.
"Well we'll have to look online," Kraft joked.
Robert Kraft handing out victory cigars, including a special visit to TB12. pic.twitter.com/4GVyJdbrfw— Dan Hanzus (@DanHanzus) February 6, 2017
The best guess here is that someone from the NFL decided to grab the jersey. Brady's performance was a record-breaking one, with Brady breaking the record for most completions by a quarterback (43) and most passing yards by a quarterback (466) in a Super Bowl. He also led the greatest comeback in Super Bowl history and picked up his record-breaking fourth Super Bowl MVP.
Surely no one in the Patriots organization would jack his jersey. He's probably got plans for that, involving something special at his house.
Although the NFL may want to put it in Canton instead. While they're at it, they can probably let Brady pass Go and just head on in, too.
If someone did actually steal the jersey, let's hope it does appear online (as Kraft noted) or, even better, security cameras captured the thief's identity -- and some justice is served up.