A year ago, Jarrett Arakawa was the inexperienced freshman, learning on the fly as he worked his way into the starting rotation.

Now, he’s considered a seasoned veteran, one of only two returning starters with legitimate Division I experience.

Not bad for someone yet to begin his sophomore season.

The 6-foot left-hander from ‘Iolani shouldered an important load last season. By the third series of the year, he had worked his way from the bullpen to a starting spot. When WAC play rolled around, he was the team’s No. 2 starter.

UH won six of the final eight games he started in the regular season and he pitched at least five innings in 10 of his 13 starts.

Without him, it’s unlikely the Rainbows would have won a share of the regular-season WAC title.

"To be honest, it took me by surprise, but I came in with no expectations," Arakawa said. "I thought I could get some innings in, hopefully, and I wanted to pitch, obviously, and things just seemed to work out for me."

Arakawa will fill a crucial role for the Rainbows this season. He and opening-night starter Matt Sisto will carry the bulk of the pitching load early as the top two starters on a staff filled with potential but low on experience.

Freshman left-hander Scott Squier, a highly touted recruit, is expected to make his UH debut on Monday against Oregon.

Junior-college transfer Jon Flinn could start Sunday — if he doesn’t pitch before then — or the Rainbows could turn to another 6-foot-6 right-hander in Corey MacDonald.

Either way, the goal is the same, head coach Mike Trapasso said.

"Not having the depth in the bullpen, which is kind of the unknown right now, we’re going to ask our starters to give us seven innings," he said. "If they go out after five, we’re asking a lot out of our pitching staff because we just don’t know what we’re going to get out of our bullpen just yet."

Seniors Jesse Moore and Brent Harrison are the two known quantities in the ‘pen. Both threw more than 30 innings last year and Moore started seven games.

Moore has spent his entire UH career rotating between pitching and playing middle infield, but will spend his senior season on the mound, helping the Rainbows where they need it the most.

"I just love winning, and whatever I can do, whether that means coming out of the bullpen or starting or even pinch-running, whatever," Moore said. "As long as we’re doing well as a team and getting a ‘W’ in the win column is all I care about."

The closer role has been a no-brainer in recent years. Lenny Linsky, a second-round draft pick of the Tampa Bay Rays, set a UH record with 26 saves over a two-year period.

To start, UH will take a closer-by-committee approach, with freshmen Lawrence Chew, David Longville and Kyle Dowdy all getting a shot depending on matchups.

"Until we get them out there, we won’t know," Trapasso said.

Here’s a closer look at the 2012 UH baseball pitching staff:

POTENTIAL STARTERS

Notes: UH lost half its pitching staff from last year, but returns Sisto and Arakawa, who finished 1-2 in innings pitched. Sisto serves as the ace of the staff for the second year in a row and has won at least five games in each of his first three seasons. Squier was drafted in the 21st round out of Greenway High School in Phoenix by the Detroit Tigers but decided to go to college. Little would have been a major contributor this season but fractured his ankle over Christmas break. He’s expected to redshirt and play in 2013.

RELIEVERS

Notes: Moore will likely pitch in multiple games per series. Longville has thrown well as a freshman and Dowdy might have the best arm of the bunch. Chew could see an extended amount of work, especially in lefty-lefty matchups. O’Rourke and MacWilliam are back after redshirting last year. Welch pitched only seven innings as a junior but posted a 2.57 ERA.