Watch: Colts rookie taunts Eagles fans after preseason touchdown

It definitely takes some confidence to go into that stadium and do that sort of thing in a regular season game, let alone a game that doesn't even count.

Richardson finished the game 6-of-17 passing for 78 yards, while also rushing for 38 yards.

He entered the NFL as one of the most intriguing prospects in the draft because his ceiling is so high. But he struggled with accuracy and had such a small body of work in college that he was slapped with the "project" label going into the draft. The Colts took him with the No. 4 pick and almost immediately turned their offense over to him as a rookie.

He has shown flashes of the potential the Colts expected this preseason, and head coach Shane Steichen seemed impressed overall with his performance.

"Shoot, I thought he did a solid job. We scored three out of the first four drives, which is good," said Steichen after the game. "The two-minute drive wasn't what we wanted, but we'll go back, look at the tape. I thought he did some really good things and some things we've got to clean up as well."

The upside is massive when it comes to Richardson, but there are no doubt going to be some growing pains ahead given his lack of experience and the lack of talent around him on the Colts' offense. That talent could take an even bigger hit if the team ends up trading star running back Jonathan Taylor over the coming days or weeks, taking away Richardson's safety net.