Columbia. Mo. ? A University of Missouri football player died Tuesday after collapsing during a voluntary, non-contact workout with teammates.

University Hospital spokeswoman Mary Jenkins confirmed the death of Aaron A. O’Neal, 19, a red-shirt freshman linebacker from the St. Louis suburb of Creve Coeur. The cause of death was not immediately available.

“I can’t begin to express how deeply saddened we are by this loss,” coach Gary Pinkel, who was out of town Tuesday, said in a statement. “Aaron was a quality young man who was well-liked and respected by his teammates and coaches.

“We are all very shocked and hurt right now, but the most important thing we can do is to focus on Aaron’s family and to assist them any way we can.”

O’Neal was listed third on the Tigers’ depth chart at middle linebacker.