How do you know that Stephens doesn't have the mental tools?
You're so wrapped up in Coleman that you say whatever you think can change people's minds.
Of course the injury is what made him look bad at the spring game. He broke his throwing wrist less than two months ago. He missed almost all of spring camp, yet he still got on the field and tried to compete. That shows the staff something, as it does with his teammates too.
He didn't play, couldn't work out his throwing arm, and lost time to refine his game under a true QB coach.
This competition won't be over until the fall, no matter how much you want a Tennessean running the offense.