LOS ANGELES >> Matt Barkley’s progression at Southern California has taken him from a heralded freshman who sometimes made questionable decisions to one of the best quarterbacks in college football.

So once he finished his junior season, the general belief was that he would leave the Trojans for the NFL. He was, after all, already a polished quarterback and was expected to be a high NFL draft pick.

But when the time came to make a decision, Barkley surprised just about everyone. He was coming back, forgoing a big payday in the NFL for one more college season and a chance to play for a national title.

And with Barkley back, the Trojans are among the front-runners to win a title.

“I assume he would have been a top-5 pick, totally ready to go in and be the face of a franchise and be ready to play in the NFL,” USC coach Lane Kiffin said. “His situation was different, and I think it was about him wanting to do something special. What some people have written, he may be able to go down as the most historic Trojan ever if we do big things this year.”

The Trojans certainly have that chance.

The past two seasons, USC has been ineligible for the postseason because of NCAA sanctions.

Now, the Trojans are bowl-eligible again and have the type of players who could make not just a bowl run, but contend for much more.

There’s Robert Woods, one of the nation’s most dynamic receivers who’s expected to be healthy after battling an ankle injury last season. Complementing him, along with giving Barkley another option, is Marquise Lee, a could-break-one-any-play receiver who’s expected to be more polished in his second season.

Curtis McNeal, who ran for over 1,000 yards last season, is back and leads a deep running back corps, one that should be even better with the unexpected arrival of Penn State transfer Silas Redd.

USC has plenty of playmakers on defense, too, led by safety T.J. McDonald, who also bypassed a shot at the NFL, and cornerback Nickell Robey.

Leading them all will be Barkley, a Heisman Trophy favorite who turns what would have been a good team into potentially a great one.

“Our leader is back,” McNeal said. “Having your leader to lead you in battle, it just motivates you even more to go get what we want.”

Barkley was highly touted as a freshman, expected to be the next in a line of star quarterbacks at USC, following in the footsteps of Carson Palmer, Mark Sanchez and Matt Leinart.

He didn’t quite live up to the billing as a freshman, throwing for over 2,700 yards and 15 touchdowns, but with 14 interceptions and occasional ill-advised throws.

Barkley progressed the next season, getting a better grasp for the game while throwing for nearly 2,800 yards and 26 touchdowns with 12 interceptions as a sophomore.

He took an even bigger step last season as a junior, finishing sixth in the Heisman voting after throwing for 3,528 yards and a team-record 39 touchdowns while completing 69 percent of his passes — another school record — with just seven interceptions.

After a season like that, the consensus was that Barkley was headed to the NFL. Even he thought he was going before changing his mind — and the fortunes of the Trojans this season.

“Right after we played UCLA I was on an emotional high, and the way we finished out the season, I thought for sure I was going to the NFL,” Barkley said. “But once that settled down, and I started looking into it all, I think I made the right call.”

Barkley’s return gives the Trojans a chance to burst out of what had been a dark time.

USC spent the past two seasons without a chance to play in the postseason, thanks to NCAA sanctions tied to former Heisman Trophy-winning running back Reggie Bush. The Trojans also lost 30 scholarships, forcing Kiffin and his staff to get creative with the depth chart and in recruiting, while leaving the team bereft of depth.

USC’s roster is still thin because of the sanctions, but the postseason ban has been lifted, giving the players something to play for other than pride.

And, in a way, the past two years may have helped the Trojans. They held it together with no hope of playing in a bowl, winning eight games in 2010 and 10 last season.

Now, they’re using the built-up frustration as motivation.

“I do think that the sanctions have brought our team closer together and strengthened us in a way that I didn’t anticipate,” Barkley said. “It made us stronger in terms of character and, you know, it allowed us to face adversity in a unique way that guys our age aren’t really used to.

“It seemed all bad at first, but ultimately, I think it worked in our favor for this point where we are today.”

Which, thanks to Barkley’s return, is in position for a national-title run.