LOS ANGELES -- Pete Carroll says the only reason he is leaving Southern California to become Seattle Seahawks coach is because the challenge was too good to pass up.

The Seahawks hired the charismatic coach away from USC on Monday.

At a news conference later on USC's campus, Carroll said "It hurts to separate."

Carroll's departure ends one of the most successful runs in college football history. He was 97-19, with two national championships and seven Pac-10 titles in nine seasons at USC.

He also leaves with the football program facing an NCAA investigation.

Carroll says his decision to leave has nothing to do with the investigation. He says he thought he would be at USC "forever."

Carroll's resignation caught his players off-guard. The group that straggled into Heritage Hall for an afternoon meeting chose USC largely on the strength of Carroll's success and charisma, but they returned to classes Monday with no idea what was next.

"I kind of didn't want to come to the meeting today, but it's something you've got to do," said tailback Allen Bradford, who will be the Trojans' top returning rusher with Joe McKnight's early departure for the NFL. "How he got us training and competing, I don't think that's ever going to leave us. The new coach coming in is going to see this team is hungry and wants to win."

Bradford planned to hold a players-only meeting in the locker room after Carroll's farewell address.

The hiring of the 58-year-old Carroll capped a busy weekend for Seahawks chief executive Tod Leiweke. On Friday, the team fired coach Jim Mora following just one season, and Leiweke spent Sunday completing a deal with Carroll.

"We are excited to add Pete as our coach. He brings a great passion for winning and a positive attitude that is contagious," Leiweke said.

Next up for Leiweke is to hire a general manager.

They have at least four interviews to conduct to find the general manager who will work with Carroll. Former Tennessee Titans GM Floyd Reese is scheduled to interview, along with New York Giants personnel man Marc Ross, Green Bay executive John Schneider and Omar Khan, a contract administrator with Pittsburgh.

Seattle forced out general manager and president Tim Ruskell on Dec. 3.

The Seahawks are set to introduce Carroll at their headquarters in Renton, Wash., on Tuesday.

Carroll was 6-10 in 1994 with the Jets and then 27-21 while twice reaching the playoffs from '97-99 with the Patriots.

He was hired by USC in December 2000, and by 2002 - after years of mediocrity and underachievement - the Trojans were back to being one of the elite teams in college football.

The Seahawks are also in need of some major rebuilding, just four seasons after the team made its first and only Super Bowl appearance. Seattle went 5-11 this season.

"We now turn our full attention to the hiring process for a general manager," Leiweke said. "Our intended structure is for Pete and the new GM to work in a collaborative capacity on football matters."

How much control Carroll would have over football operations with the Seahawks was a key issue throughout the negotiations.

The USC program, meanwhile, is now leaderless at a difficult time. The school has been under NCAA scrutiny for several years due as the organization investigates allegations former Trojans tailback Reggie Bush received improper benefits from a marketing agent.

Another potential NCAA problem arose last month when McKnight was forced to sit out the Emerald Bowl while the school investigated his use of an SUV that was not registered to him.

McKnight, along with star wide receiver Damian Williams, declared for the NFL draft as juniors last week.

With national signing day for college football recruits on Feb. 3, the timing of Carroll's move also puts USC's recruiting class in flux.

USC has already sanctioned its basketball program for recruiting violations involving former player O.J. Mayo, including a ban on postseason play this season. Mayo allegedly received improper cash and gifts while at USC and playing for former coach Tim Floyd, who quit in June.

Carroll flirted with the Miami Dolphins and the Atlanta Falcons in recent years, but did not take a the plunge for a third NFL stint until the Seahawks, with owner and Microsoft Corp. tycoon Paul Allen, came calling last week.

Even outside football, Carroll has become a prominent figure in Los Angeles during his tenure in the nation's second-largest media market. His charity endeavors, including his A Better LA foundation, and social work with inner city youth have earned high praise.

Oregon State coach Mike Riley, a former USC assistant and one of the first names to surface as a possible candidate to replace Carroll, agreed to a three-year contract extension Monday. If embattled athletic director Mike Garrett goes after another former NFL coach, Tennessee's Jeff Fisher and Jacksonville's Jack Del Rio are former Trojans who could be targets - although Fisher, the NFL's longest-tenured head coach, previously said he's not interested.

"Whoever we get in, I'm pretty sure he's going to be a great coach," USC defensive lineman Jurrell Casey said. "It's still a great program, great players here, and it's still going to get you to the next level."