Former USC quarterback Matt Leinart has already called his first pre-draft audible by firing Leigh Steinberg as his agent, ESPN's Chris Mortensen reported Monday night.
Steinberg confirmed to Mortensen on Tuesday that he had been dismissed as Leinart's agent.
"I'm completely at a loss for the reason why," he said. "I haven't been given an explanation."
Leinart filed the necessary paperwork with the players' union on Monday, but Steinberg says he hopes to convince Leinart to change his mind during the mandatory five-day waiting period before Leinart could sign with another agent.
Leinart could be reached for comment. Leinart is projected to be the first quarterback chosen in the NFL draft on April 29.
It is the second major blow for Steinberg, who also was recently fired by USC tackle Winston Justice, also a projected first-round pick. Justice has hired Gary Uberstine as his new agent.
Leinart is currently represented on the marketing front by Creative Artists Agency. Last week, agent Tom Condon, who represents both Peyton and Eli Manning, left IMG for CAA. This caused speculation in the industry over Leinart's next move -- whether he would leave Steinberg to be represented by CAA in entirety or drop his affiliation with CAA to avoid a potential conflict.
Steinberg has represented the first pick in the NFL draft eight times. Several past standout quarterbacks including Hall of Famer Steve Young, Warren Moon and Troy Aikman were among his clients. He represents current starting quarterbacks Ben Roethlisberger and Mark Brunell.
Chris Mortensen is a regular contributor to ESPN Insider. Information from ESPN.com's Darren Rovell and The Associated Press was also used in this report.