So what caused the confrontation between young 49ers stars Vernon Davis and Michael Crabtree on Wednesday, forcing both to leave practice?

“Crabtree’s attitude and perceived apathy toward training camp and exhibition season,” was the problem, according to Matt Maiocco of Comcast Bay Area.

SI’s Jim Trotter heard the same thing, tweeting that “players don’t like Crabtree’s

ambivalence toward preseason & camp. Love his talent, though.”

Davis apparently let Crabtree know he felt in no uncertain terms. Coach Mike Singletary didn’t appreciate the way Davis delivered his message, but it sounds like he understood the thought. Apparently, Crabtree’s disinterest has been the “elephant in the room” Singletary referred to at 49ers camp.

“[Davis] is one of the captains. He did the right thing, but he did it the wrong way. So that’s all I’m going to say about that,” Singletary said.

Crabtree was expected to suit up in last week’s preseason game, but was a scratch at the last minute. Now we wonder if there was more to the story, and whether there’s a feeling Crabtree milked his neck strain this month for all it was worth.

We think Crabtree has a great chance to be one of the best wide receivers in football for the next decade, but he’s starting to earn that “diva” label stuck on him in pre-draft workouts.