Yet when camp broke, with a week to prepare for the Trojans first game at Hawaii, your eye had to fall to the bottom of the tailback depth chart to find Allen.
He was buried, fourth in line to get in the game.
Interim coach Ed Orgeron gave him a chance to get some carries. The three backs ahead of him, Silas Redd, Justin Davis, and Tre Madden began battling injuries... and soon, Allen had shown enough in his minutes played to earn himself the starting role.
He was named the team MVP at Friday night's banquet.
"It meant a lot," Allen explained after Sunday's practice. "I never knew I was going to win it and it meant a lot. I want to thank the coaches for believing in me, thank the coaching staff, thank [running backs] Coach [Tommie] Robinson for giving me the opportunity, Coach [Ed] Orgeron. Words can't describe what it means to me and I just want to thank the team."
"He's improved in every area of his life since being here at USC," interim coach Clay Helton explained. "He's the guy in the spring, if you remember when the injuries were there, he said 'Don't worry, coach. I got it'. Then you go through this season and we have injuries and he says 'Don't worry coach, I got it.' Then you go into the Arizona game, he dives over the pile and the ball goes up and you say 'Yeah, he's really got it.'
"Thank goodness he's here. He's carried us through the second half of the season. There's a reason he's MVP."
Allen finished the regular season with 699 yards rushing, including 12 touchdowns and a touchdown reception.