Porter was held out of Auburn's 88-59 loss to Florida on Sunday as the school investigates possible contact between the player and an agent.

"Until the issue is resolved, we will withhold Chris from competition," athletics director David Housel said.

Bill Saum, who heads up the NCAA's agent and gambling enforcement division, said Sunday that a violation dealing with a sports agent will be dealt with more severely than almost any other type of transgression.

Reached at his home in Indianapolis, Saum said the NCAA expects to learn Monday if Auburn chooses to rule Porter ineligible and then seek his reinstatement by appealing to the NCAA for leniency. Saum said simply having contact with an agent is not an NCAA violation, but accepting any money or gifts would qualify as breaking the rules.

"We still don't know all the facts of the case," Saum said.

Porter, who was not officially declared ineligible by Auburn, was sent back to campus late Saturday night for questioning by school officials.

But one source said that Auburn coach Cliff Ellis was worried that it was a "bad news" agent that the program had tried to keep away from Porter.

Ellis said he didn't know who tipped off Housel and was in the dark as to what would happen next. But he did say the allegation stemmed from something that happened this season. He said he found out late Saturday night and was ordered to send Porter back to Alabama. Ellis said he implored Porter to be honest with school investigators.

"If he's made a mistake, he's paying a hard mistake now with what he's given up and what he's done," Ellis said. "He's certainly good for the college game. I hope (the NCAA) will allow him to come back and continue to contribute to this game. He made a choice to come back because he could have left a year ago."

Porter, Auburn's leading scorer at 14.6 points a game, was projected as a first-round draft pick a year ago. But rather than leave school, he chose to return for his senior season. Ellis said the 6-foot-7 forward should be praised for staying in school and being on track to graduate by the end of the summer, especially because he he failed to qualify to play immediately out of high school and earned a two-year degree at junior college.

Saum didn't share Ellis' viewpoint.

"Our student athletes are well educated on what they can and can't do," Saum said. "It doesn't matter if you're going to graduate or not."

Auburn reacted quickly to the information, which was expected in light of the recent suspensions for various extra benefits across the country. Part of the 44-game suspension of UCLA's JaRon Rush was for accepting $200 from agent Jerome Stanley.

Auburn players weren't aware of the extent of Porter's involvement with an agent, but senior guard Doc Robinson said the players have been careful.

"You have to watch who you associate with," Robinson said.

Ellis said he hopes to have the situation resolved within the next two days, especially with the Tigers hosting SEC West rival and first-place LSU on Wednesday on Senior Night at Beard-Eaves Coliseum. But that might be hard to do with the information not expected to be handed over to the NCAA until Monday.

"We'll try to act quickly, but it doesn't matter that the NCAA Tournament is coming up," Saum said.

Both Ellis and Florida coach Billy Donovan wondered how they could be expected to keep agents or emissaries for agents away from players at all times.

"I can watch Donnell Harvey right now but how can I stop him out in the hall from a guy giving him some money or being handed a card or whatever," Donovan said. "There needs to be some sort of blame for the agents, too. It's not just about Porter and Auburn. There should be some sort of penalty against the agents."

Florida's Mike Miller said the Gators have been wise to agents after William "Tank" Black was accused of giving money to three Florida football players.

Andy Katz is a senior writer at ESPN.com.