Jameis upside is Unfathomable

Correct me if I am wrong, but there was not a Training Camp for anyone to beat anyone out in last season. Also, the head coach promised a certain player he would play if a certain retired QB went down. Am I missing anything?
This is the NFL, not some flag rec league. If Jameis was clearly good enough, that "pinky promise," you'll start from Payton to Taysom would be out so fast your head would spin. Payton isn't going to lose the team by playing the inferior player at any position.