Ricky Town, considered one of the nation's top recruits in the Class of 2015, decommitted from Alabama on Saturday and later in the day gave an oral commitment to Southern Cal.
Town, a 6-foot-4 junior quarterback at Saint Bonaventure in Ventura, Calif., had committed to the Crimson Tide in August. He is ranked as the No. 3 overall recruit among high school juniors by 247Sports.
The news came less than two weeks before the first day for high-school seniors to sign national letters of intent on Feb. 5. Town, a junior, cannot sign until 2015.
"Today I have de-committed from Alabama. It was an honor to get to know Coach Saban and the Alabama fans. Thank you!" Town tweeted.
Town did not offer a reason for changing his mind, but he was known to be reconsidering his decision after offensive coordinator Doug Nussmeier left Alabama for the same job at Michigan earlier this month.
Town made an official visit to Southern Cal on Saturday and then announced that he was in the Trojans' camp.
"I'm proud to be a part of the Trojan Family!" Town said via text to ESPN. "I've seen many of the top programs and what they have to offer. However, when I had the chance to get on the USC campus last week and spend time with Coach (Steve) Sarkisian and his staff, I knew after those meetings that USC is where I want to be.
"The coaches are upbeat, focused and committed to winning and I completely believe in them. I chose USC because of the tradition, the academics and the incredible coaching staff. This is an amazing opportunity to be a part of something really special. Fight On!"
Alabama could on the way to adding another quarterback. Former Florida State quarterback Jacob Coker, who visited Tuscaloosa, Ala., on Saturday, is considering a transfer to Alabama after he lost out to Heisman Trophy winner Jameis Winston in the quarterback competition with the Seminoles last season.
An Alabama native, Coker was the backup to Winston last year before he sustained a knee injury. He was released from his scholarship after Florida State won the BCS national championship.
Coker is set to graduate in the spring and would have two years of eligibility remaining. Coker's high school coach, Steve Mask, said Crimson Tide coach Nick Saban visited Coker at his home this past week.
Saban is looking to replace starter AJ McCarron next season.