It's like Kelsay is constantly surprised and unprepared when the ball carrier is in front of him.
He needs to engage his blocker with more of an LB mentality where he stands his man up, keeps his balance and is prepared to shed him in either direction while keeping his eyes in the backfield. Instead, he has kept his old DE mentality where he picks a technique ahead of time and commits to getting around one side of his blocker. When he's actually in position, it's out of dumb luck.