Barker, a junior and the football team's leading receiver, said in a Twitter message Sunday he will seek to transfer to another school for his final year of eligibility.
He said Thursday his decision came after a heated discussion with his coach about his availability to play after a high ankle sprain forced Barker to miss the last three games.
"Both he (Kill) and the trainer felt I should be healthy right now. Coach Kill blew up on me that I should have been ready a week and a half ago. For me and my future, I just felt it was best to move on now, rather than wait two months," Barker told the St. Paul, Minn., Pioneer Press.
Barker added Kill apologized to him, moments after the conversation, but also made it clear Barker's final-year scholarship would have to be earned.
"He said to me I wouldn't be playing in the bowl game, and I had to work my way from the bottom back up," Barker said.