The Pistons' Brandon Knight got whistled for traveling late in the first quarter Sunday night and raised his arm in frustration, elbowing the Bulls' Jimmy Butler squarely in the face.

It looked unintentional, but as Knight approached Butler to apologize, Nate Robinson stepped in with a shove. Then the Pistons' Kyle Singler pushed Robinson.

Lawrence Frank, the diminutive Pistons coach, summoned his inner Jeff Van Gundy as he jumped in to break up the brouhaha.

Robinson and Singler received double technicals, and Knight was assessed a flagrant. Butler hit both free throws.

Asked if the elbow left a mark on his grill, Butler rubbed his nose and replied: "I hope not. He messed my swag up with that one."

But Butler said there was no doubt it was inadvertent.

"I've known Brandon for two years," Butler said. "He apologized, nothing major."

Then turning to neighbor Marquis Teague, Butler joked: "Kentucky guys, I tell you."

Taj Gibson got a measure of revenge for his teammate about a minute later, elbowing Knight as he came through the lane. Gibson nodded in approval of the foul call.

Foul call? The NBA's decision to upgrade a Gibson foul on LeBron James from a regular shooting foul to a flagrant foul surprised Bulls coach Tom Thibodeau.

"I guess we have to call the league and get clarification on that," he said. "I didn't see it that way. I still don't have a good understanding of what a flagrant foul is. By rule it's unnecessary, excessive. I thought I got some clarity last year, but apparently I didn't."

James complained after Wednesday's game of fouls he deemed "not basketball plays."