Depends. A lot skip bowl games, and with Walker he had concussions.
SFnL, I think it's well-documented that he wasn't a shining star in the eyes of the coaching staff. I think they pretty much said flatly that he quit on the team. The concussions were one thing, but I think he was cleared to play way back in November.
It's even in his NFL.com draft bio. Talks about what a physical beast he is, but that it was always difficult to get consistent work out of him, and that the NFL scouts were likely to receive a lot of negative press about him from the OU coaching staff.
http://www.nfl.com/draft/2017/profiles/charles-walker?id=2557999
WEAKNESSES
Has had concussions in each of last two seasons. His football character called into question by coaching staff after he failed to come back from October 1 concussion and left team with two regular season games remaining to prepare for NFL draft. Effort level and motor fluctuates. Was a relative non-factor in all four of the games he played. High cut and struggles to maintain his ground against double teams. Lacked urgency as a pass rusher that he showed in 2015. Needs to add a rush counter when initial charge is foiled. Will lay on blocks at times. Needs quicker shed with tackle-ready posture.
SOURCES TELL US
"I'm not really a fan but I'm sure our coaches will be. He has talent but he's just so inconsistent. He has quickness and strength but then will just disappear during the game. He has enough flashes on tape that I'm sure our coach will want to work with that." - NFC regional scout