Now that he’s made it onto the field, USC freshman Oluwole Betiku Jr. is ready to contribute

USC defensive end Oluwole Betiku Jr. was so overwhelmed to see the first action of his career on Saturday that his mind momentarily went blank.

"It was wonderful,” Betiku said. “But I got onto the field, I forgot everything, man."

USC has high hopes for Betiku, a five-star recruit from Gardena Serra High. His chiseled frame already resembles that of a professional player, though he is only a freshman. He’s listed at 6 feet 3 and 250 pounds (he says he now weighs 260 pounds).

But Betiku is a raw talent. He started playing football only recently, having lived in Nigeria until his sophomore season in high school. He was, in other words, a good candidate to take a redshirt season.

Trojans Coach Clay Helton indicated last week that he didn’t want to keep Betiku off the field. He played one snap against Colorado, a total that is likely to increase if USC is to justify burning a season of Betiku’s eligibility.

"We looked at it and said, OK we're playing Colorado, Arizona, Cal, Oregon coming up, you're playing these teams that you could play anywhere from 80 to 100 plays in a game, we need that third-down pass rush,” Helton said. “And he gives it to us."

Betiku said he hadn’t discussed a possible  redshirt season with the coaching staff.

“I just come about my business, do my practice and whatever the coaches tell me to do, I just do it,” Betiku said.

USC’s thin defensive line can use the depth. For now, Betiku’s role will be limited to third downs. Helton said Betiku’s understanding of schemes has advanced, but USC is taking his progression gradually. The coaching staff still haven’t given him first- and second-down assignments.

"Even though he looks like a 30-year-old man, he's a true freshman," Helton said.

Jackson meets ‘five’

Adoree’ Jackson was standing outside the Coliseum on Sunday, chatting with his former teammate Kevon Seymour, who now plays for the Buffalo Bills, when he looked up.

Not far away, Reggie Bush was striding past a banner listing the accomplishments of USC and its players. Bush won a Heisman Trophy at the school in 2005. He was taken in the first round of the NFL draft.

His name was not listed.

NCAA sanctions have mandated that USC dissociate with Bush, whose name has been scrubbed from the campus and USC’s media guide. He returned to the Coliseum for the first time since the penalties on Sunday, as part of the Bills’ win over the Rams.

As Jackson chatted, and Bush walked past the banner, they made eye contact.

How would Bush react?

"I went up to him,” Jackson said. “But I think he knew me."

The two chatted — Jackson preferred not to reveal the content of the conversation. ("We were just chopping it up," Jackson said.)

Jackson, like many current USC players, grew up idolizing Bush. He said he’d planned on attending the game on Sunday even before the Bills signed Bush in August.

Bush has been guarded in most public comments about USC. In an interview with The Times last week, Bush said, “It’s the memories I have there that outweigh the pain by a tremendous amount. I choose to remember the great times there.”

According to Jackson, he has at least followed the team.

"It was pretty cool," Jackson said.

Davis  out

Running back Justin Davis has been ruled out for Saturday’s game at Arizona, Helton said. Davis sustained a high ankle sprain against Colorado and hasn’t practiced this week.

Ronald Jones II will start in his place.

Helton said he has “full confidence in the three backs that we have.”

Quick hits

Right tackle Zach Banner (ankle sprain) has been cleared to start against Arizona. Chuma Edoga will serve as his backup. … Tight end Taylor McNamara (back strain) is probable.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand