The RSL midfielder touched off a tussle in the 18th minute of the 2-1 win over Chivas USA. Two players were ejected and two more received yellow cards.

Mathis was one of two who got the red, which brings with it automatic ejection and suspension from RSL's game against the New England Revolution on Wednesday.

Chivas midfielder Esteban Arias also was sent packing for his part in the five-minute melee.

It started when Chivas defender Jesus Ochoa fouled Mathis hard from behind. As Mathis lay on the ground, Chivas forward Isaac Romo kicked the ball at him. Mathis jumped up off the ground in pursuit of Romo.

From that point on it's difficult to pin down the course of events.

Ochoa was given a yellow card, but referees didn't announce it until after the second half had begun. Mathis reached Romo, but he never made contact with the Chivas player, though he did try.

Small shoving matches broke out across the field during the fracas, and it wasn't until a few minutes into the ruckus that Mathis was ejected. He said he didn't know what he did to merit the red card.

"You're going to have to ask the referee, because I sure don't know why I got thrown out," Mathis said. "I wasn't really talking with anybody else on the team. It was just a big scuffle. I don't really even know what happened. I was down there on the ground, I got kicked with the ball, some guys said this guy kicked it, then it just turned into a big pile."

RSL coach John Ellinger said even he wasn't sure why Mathis got the card.

"It's an intense league, emotions run high at times . . . ." Ellinger said. "Even Eddie [Pope] would've gotten upset with that one, and he's about as casual as you get out there."

This much is certain: His teammates rushed to his side.

"I really felt Clint was justified in his reaction," teammate Jason Kreis said. "I didn't see him make contact with another player."

An ESPN2 halftime show - the game was a part of ESPN2's Soccer Saturday package - featured an in-depth interview with Mathis, who was showered and dressed by the time the break arrived.

General manager Steve Pastorino watched the replays of the fight - in which it appeared Romo took a dive when confronted by Mathis - and told Ellinger that RSL wasn't in the wrong.

"Steve told me at halftime that we'll be totally vindicated, based on what the replays have shown," Ellinger said. "And I've got to believe that's going to happen. His red card was a mystery."

Mystery or not, RSL will not have Mathis when it plays at the Revolution on Wednesday. The player had already initiated an appeal, but only to reduce the $500 fine that comes with it. In MLS, a card stands unless a referee issues it to the wrong player.

So Mathis will stay in Salt Lake when the team leaves for Foxboro, Mass., early this week.