Univ. of Texas star defensive back B.J. Foster won't have full use of one of his hands for a bit ... his coach says he broke it punching his car in a fit of anger.
Tom Herman told reporters Thursday the junior came out to his vehicle in a parking lot ... and when he saw it had been hit (plus, the other driver didn't leave a note) -- he exploded.
"He got a little angry and decided he was going to take it out on the car bumper," Herman said.
The result? The coach says Foster broke the fifth metacarpal in his hand punching the ride and will require a cast to heal the injury.
"We had a long conversation on that," Herman said. "Every time, in my 45 years on a planet, when a player gets in a fight with an inanimate object, usually the inanimate object wins."
Good news, though ... Herman says Foster will still be able to work out with the Longhorns despite the cast -- and is expected to make a full recovery in time for the season.
Ice up, B.J.!!!