Matt Barkley will surely go pro -- but oh, what if he returns?

The chanting was more like pleading. The waves seemed more like hand wringing.

It was a farewell that didn’t feel fair, and doesn’t bode well, and as much as USC fans want to hug Matt Barkley, they probably also want to shake him.

How can he leave when the party is just getting started?

PHOTOS: USC vs. UCLA

In what was almost certainly his final game as a Trojan Saturday, the USC quarterback threw for 423 yards and six touchdowns in a 50-0 stomping of lifeless UCLA. But all those numbers could be boiled down to three words.

“One ... more ? year.”

The words were sung by the students behind the USC bench. They were repeated by the adults sitting above the Coliseum tunnel. They were even written on the belly of 11 kids lined up along the front row, one letter for each chest, body begging at its best.

“One ?more ?year.”

Barkley answered them in the sort of play that will probably move him up into the top seven in the NFL draft next spring, an answer that can best be described in three other words.

“Not ? a ? chance.”

Sorry folks, but the kid is turning pro, the kid has to turn pro, even his coach admitted afterward that he would be “unique” if he stayed.

“I probably shouldn’t be saying this,” said Coach Lane Kiffin. “But unless he just wants to do it to be a special Trojan, he’s not coming back.”

Barkley loves being a special Trojan, and actually grew sentimental late Saturday in the press room when he heard his teammates singing the fight song outside.

“Oh man, there’s the fight song,” he said. “I’m sorry, I get chills just hearing that.”

But those chills are likely not worth the guaranteed money given a top-10 NFL draft pick, as much $20 million for someone in Barkley’s range. Remember, this is a guy who was so ready to start his career, he left high school three months early.

There seems to be little doubt about whether he will stay. The bigger question now is, has any early-departing USC quarterback left more on the table when he goes?

“I feel like we’d go a long way if he came back,” said receiver Robert Woods, who caught 113 yards worth of passes, including two touchdowns.

A long way? How about, all the way?

If Barkley came back to USC to lead them in their first year off probation, the young Trojans would be one of the favorites to win the national championship. Goodness, as well as they are playing at the end of this year, if they were allowed to compete in a bowl now, the only appropriate one would be the BCS title game.

Seriously, who else but Alabama or LSU would be definitive favorites over the Trojans right now? Who else can match the Trojans combination of speed, toughness and quarterback play?

Asked if he felt his team could beat anybody, for the first time and last time this year Barkley acknowledged in the affirmative.

“The way we’re playing now, yeah,” he said. “The way the guys are feeling the mojo ? it’s something special that I’ve never been a part of.”

Despite playing Saturday in an emotional game that usually defies statistical trends, the Trojans not only outgained UCLA, 572 to 385 yards, but also committed zero turnovers while being assessed just five penalties. UCLA might be sloppy and sinking in the final days of Rick Neuheisel, but are they really that bad? It’s more like USC has become really that good.

While the Bruins head north for a bizarre Pac-12 championship game matchup against an Oregon team that might be favored by 60, the Trojans had to be content with T-shirt that read, “USC Football 2011 South Division Champions.”

If Barkley came back next year, those T-shirts could quickly become relics as the Trojans returned to national prominence, and not just as a team. Barkley would also be the Heisman favorite from the start of the season, the award his to lose.

Barkley’s performance Saturday night probably earned him an invitation to New York for this year’s Heisman ceremony, but he can’t win it, even after throwing a school-record 39 touchdown passes. He can’t win because he got hot too late to catch the likes of Alabama’s Trent Richardson, Baylor’s Robert Griffin III and Stanford’s Andrew Luck.

Next year, though, everyone would be chasing him, and everyone would be chasing the Trojans and, again, has any Trojan ever willingly walked away from so much?

“I know, I know,” said junior tackle Matt Kalil, who shares Barkley’s dilemma. “Its going to be a really, really tough decision for all of us.”

Barkley wouldn’t discuss the decision Saturday, saying, “This night is too special to take from it. I don’t want to worry about my future now.”

That’s typical classy Barkley. That’s why he will leave not only with huge cheers and chants, but also with the enduring gratitude of USC fans for competing so proficiently and professionally under such negative circumstances. There may have been a dark cloud over the program during USC’s two years of postseason banishment, but it never seemed to shadow Barkley.

When the embattled team needed a strong face, Barkley showed up. When the disillusioned fans needed a word of encouragement, Barkley spoke out.

The two no-bowl seasons could have sent the team circling the drain, but Barkley was the big blond sink stopper, collecting all the Trojans energy around him, refusing to allow their ambition to disappear.

“It was us against the world, it was like everybody hated us, and yet we all hung in there and kept playing,” said Kalil. “Matt was a big part of that.”

And now that he’s probably gone, leaving the talented young offense in the hands of an untested quarterback, what happens next? Earlier this year it seemed like the Trojans would be lost without him, but after Saturday night, the mind wandered back to 2002.

Remember when Trojans finished the year with an Orange Bowl victory that vaulted them back to national prominence? Remember how senior quarterback Carson Palmer then turned pro?

The following year, an unknown kid named Matt Leinart led them to a national title. So even without Barkley, anything can happen.

“We’re the best program in America. We’re not about one person,” said Kiffin.

For long chilling moments Saturday night, USC did indeed feel like the best program in America. But, my, how that one person will be missed.

bill.plaschke@latimes.com