University of Hawaii running back Paul Harris has learned two no-no’s in college football: no bullpens and no pouting.

The two restrictions were related as Harris, who rushed for 1,132 yards as a junior in 2015, adjusted to his role this season as the third back in a system that mostly rotated two backs.

Harris was used to being a “feel” running back who improved with successive carries. “Through the course of the season, I had to jump in there,” Harris said. “The first few games, I wasn’t used to that.”

Unlike baseball, for instance, a football reliever does not have a spacious warm-up area. Harris relied on stretching, jogging in place and studying the on-field action while waiting to be summoned. Harris has entered as early as the Rainbow Warriors’ second series or as late as their 51st offensive play.

“Now that I know that’s my role, I got accustomed to that, and I’m ready to make plays,” said Harris, who averages 10.7 yards on his first carry. “That comes from watching more film and buying in and mental reps.”

Harris was 180 pounds on a 6-foot frame when he transferred from Ventura (Calif.) College in June 2015. This past offseason, he went through intensive training to gain strength and bulk. “It definitely helped me absorb the hits,” said Harris, who now weighs 200 pounds. “Aches and pains aren’t like what they were last year.”

Harris also took “spin” classes from teammate Steven Lakalaka, who organized cone drills and rope-jumping workouts to improve agility. Harris is averaging 7.3 yards per rush, including 4.3 yards after contact or spinning free from would-be tacklers.

Coach Nick Rolovich praised Harris’ diligence and attitude despite a diminished role to open the season. Diocemy Saint Juste, who has a team-high 691 rushing yards in nine games, and Lakalaka, who has excelled in short-yardage situations, have received most of the carries this season. Saint Juste did not play in the past two games because of shoulder issues.

“He could have pouted, but he didn’t,” Rolovich said of Harris. “He’s very unselfish. He wants to win. I think they all do.”

Harris said: “I’ve been in this situation before in Ventura. I was a big supporter to my teammates. It’s the same here. It’s all love. My teammates are brothers, especially the group that we have as running backs. I want them to shine. I want everyone to shine.”

Harris, who rushed for 145 yards against Boise State last weekend, is expected to have an expanded role in Saturday’s road game at Fresno State.

“He’s continued to work on his craft,” Rolovich said. “We knew he had speed. But to be a complete back, you’ve got to be a factor in pass protection and blocking. They each have their roles. He was the odd man out. It wasn’t his ability or his attitude. It wasn’t anything like that. It was getting an opportunity in a crowded backfield. I’m very happy he took advantage of it.”

Harris said he also is focused on the paper chase.

“I’m supposed to graduate in May,” Harris said. “I’ll be the first one in my family to get a degree. That’s an accomplishment. I want to set the bar for my future kids.”