Hawai'i will be short-armed when it opens the Western Athletic Conference season this weekend against four-time defending champion Fresno State.

Starting pitcher Matt Sisto is out for the series and Nate Klein's recovery has taken a turn for the worse.

Sisto, usually the second-game starter of a series, injured his right biceps in Saturday's game against Gonzaga. He is expected to return for next week's series at Sacramento State, UH coach Mike Trapasso said.

"We're keeping our fingers crossed if that's the case," Trapasso said.

Less of a certainty is Klein, who made his first appearance in three weeks Saturday with a perfect inning of relief. He had left his March 12 start against Southern California after 1 2/3 innings because of a tender shoulder. Trapasso said Klein had a setback in his recovery during a bullpen session on Tuesday. There is no time table for his availability. Klein visited his doctor yesterday.

It's not the most propitious way to start conference for the Rainbows (16-12), winners of four of their last five, against the Bulldogs (17-12), who are on a four-game win streak. It just means others will have to pitch in.

"Any time you have injury questions or depth questions with your pitching, the easiest way to solve those is to go out and score a bunch of runs every game," Trapasso said. "For us to win, we'll have to score and hit better than we did last week (against Gonzaga)."

The Rainbows will open the series with their most consistent starter in Josh Slaats (3-1, 1.03 earned run average), the reigning and three-time WAC Pitcher of the Week. He pitched seven scoreless with 10 strikeouts in a 3-1 win against Gonzaga his last start. He has pitched 20 consecutive scoreless innings.

"I'm excited," Slaats said of the WAC opener. "It's a different atmosphere when the WAC starts off. The games get more intense."

For Saturday's doubleheader, Zach Gallagher (3-1, 3.74), who has filled in during Klein's absence, will start the nine-inning opener. Sam Spangler (2-3, 4.81) will start the seven-inning nightcap.

Sunday's starter is pending. If Alex Capaul (4-1, 4.40) isn't used in relief after the first three games, he is likely to get the start, Trapasso said.

The Rainbows, whose strength of schedule is No. 15 by BoydsWorld, know their non-conference schedule should have prepared them for conference.

"We played such a good non-conference schedule that you expect the WAC not to be as good," UH senior first baseman Kevin Macdonald said. "But it's always as good as the non-conference teams, so we just have to make sure we prove it, play as well as we've been playing."

As for the Bulldogs, they return to the scene where they captured their fourth title in a row. They came out of the one-loss bracket to beat New Mexico State twice on the same day.

"When WAC play starts, they're always ready to go," Trapasso said of FSU. "This will be as good a team as we'll play all year. They always are."