A more mature Matt Barkley is poised for his shot on the big stage

USC’s game Saturday night against top-ranked Oregon is the biggest of the Trojans’ season — and of Matt Barkley’s career.

So take a good look at a player at the midpoint of what will probably be a three-year stay.

USC’s sophomore quarterback insists that he has not yet considered the possibility of bolting to the NFL after the 2011 season.

But, really, would there ever be a better time if he continues playing this way?

Barkley has passed for 20 touchdowns with only four interceptions while leading a sanctions-strapped team that is two last-second field goals from being undefeated.

He is commanding the huddle, making smarter decisions, and consistently executing throws that former coach Pete Carroll envisioned when gushing about Barkley’s potential.

Now, with the college football world watching to see if a No. 1 team will fall for a fourth consecutive week, the Newport Beach native is back in the spotlight and on the fringe of Heisman Trophy consideration.

A year from now, he might very well be at the forefront of that discussion — and of NFL draft projections as well.

Consider: Former Trojans quarterback Mark Sanchez started only 16 games before becoming the fifth pick in 2009.

Barkley has already started 19 games and, if he remains injury-free, could have at least 18 more to develop before he’s eligible to turn pro.

“I hate to see guys leave early,” longtime NFL draft guru Gil Brandt said. “But if he continues to do what he’s been doing, there will be a big pot of gold at the end of the rainbow.

“He’ll be able to buy Newport Beach, as expensive as that place is.”

The last time Barkley stood on a stage this big, he was playing his second college game. The Trojans beat Ohio State before a crowd of 106,000 at Ohio Stadium with a fourth-quarter drive, a beyond-his-years feat for any freshman quarterback.

Saturday night is different.

Barkley is no longer a timid boy wonder, handing the ball off and questioning his place in calling out older players.

This is his team.

Teammates bestowed their blessing by electing him a captain.

He embraced it by passing for five touchdowns in the opener against Hawaii, and then wobbled some with turnovers and shaky moments in the next three games. But Barkley put the Trojans in position to win what became dramatic last-second losses to Washington and Stanford.

Then came a quiet but giant step: another five-touchdown performance against California.

One of those scoring passes, to freshman wide receiver Robert Woods, was delivered on the run and into the only window possible for a completion, in a corner of the end zone. Barkley made it look so effortless — “The game has slowed down,” he said — it largely went unnoticed.

“I don’t know if I would have been able to make that throw last year,” he said.

Coach Lane Kiffin compared Barkley to 2004 Heisman winner Matt Leinart after the same number of starts. More talent surrounding him on offense, and a defense that produced numerous turnovers, helped Leinart that season. But Kiffin said one of Leinart’s greatest talents was finding ways to make “out-of-rhythm” plays on third down, turning troublesome situations into first downs.

“That’s what really good quarterbacks do,” Kiffin said. “Matt Barkley has just started doing that.”

In the last three games, he also has stopped making ill-advised throws.

Last season, Barkley was visibly uncomfortable throwing the ball out of bounds and moving on to the next play. Now, it seems effortless.

“That’s really clicked and I’ve understood how to play like that rather than just understanding it on a chalkboard,” he said.

And Barkley’s improvements go beyond what fans can see.

“It’s just his demeanor; the way he talks,” senior fullback Stanley Havili said. “A couple of games last year you could tell he was shaken. But this year he’s kept his cool and the players feed off that.”

Barkley showed poise months before the season began when the NCAA handed down penalties that included a two-year bowl ban, potentially eliminating his chance of playing for a national title before leaving USC.

He became the face of the program, addressing the media and coolly, sometimes defiantly, proclaiming that the Trojans would persevere. And have fun doing so.

“He’s like the kid that goes to Disneyland and can’t wait to go from ride to ride; that’s how he approaches everything,” said Bruce Rollinson, Barkley’s coach at Santa Ana Mater Dei High. “The difference is his makeup. By the third or fourth time, most kids aren’t fired up anymore, but he still is.”

Not that Barkley wasn’t disappointed.

His father noticed.

“But we talked about it,” Les Barkley said, “and his attitude was, ‘Let’s focus on the positive — you’ve got 13 games to play and you never know what bluebird opportunity may come up.’

“Saturday is a great example.”

Barkley said he has mostly put last season’s 47-20 loss to Oregon at Autzen Stadium out of his mind.

Rather than focus on revenge, he hopes to build on recent performances and the confidence that Kiffin has shown in him.

Former offensive coordinator Jeremy Bates called “more of a possession game,” Barkley said.

That’s not Kiffin’s way.

“It’s almost sometimes like he’s using us to play real-life ‘Madden,’ ” Barkley said, referencing the NFL video game. “He sees everything perfectly like that and, because of the athletes we have here, he can make those visuals come true.”

So, maybe Carroll’s gushy pronouncements about Barkley were accurate, if premature.

Barkley referenced a recent comment by Jim Harbaugh, when Stanford’s coach said his wife and Cardinal quarterback Andrew Luck “have a lot in common in that they’re just both perfect.”

“That’s a little over the top,” Barkley said, laughing. “[Carroll] never said that, OK? He never went that far.

“He definitely praised me, and got on me when he had to, but he didn’t say I was perfect.”

gary.klein@latimes.com

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