Chicago Bears Quarterback Mitchell Trubisky was signing autographs for several fans at Bears camp, including one guy who put on a Trubisky jersey and bucket cap to join in on the fun. 

The mystery man was none other than his own backup, undercover fan Chase Daniel:

Follow along with Chase Daniel as he attempts to get player autographs at Bears Training Camp. That dude doesn’t look like an NFL player, but a lot of 2nd and third stringers are barely recognizable. 

https://www.youtube.com/watch?v=HXNYdNIiZlw