I am not sure that's the word you were looking for. It's not like he is a 'troubled' teen messed up with drugs or something, right? I know that this isn't the New York Times, but try to be more careful... if this was my kid, I would be very angry after reading that. Maybe this:

The ex-LTHS quarterback Garrett Gilbert, who lost the Longhorn starting job after some poor outings and a season-ending injury, ...

EDITOR - GOOD POINT AND IT IS NOW CHANGED