Five baseball games in four days are taxing enough on a pitching staff.

Unfortunately, that's only the beginning of the challenge that awaits the Hawaii baseball team as it heads to Oregon for the Rose City Invitational that gets under way tomorrow.

The Rainbows will be without junior right-hander Nate Klein (0-1, 4.21 ERA), who has a muscle strain in his forearm. Klein is second on the team in innings pitched (251/3), and leaves the Rainbows a starter down as they get ready to play nine games in 11 days.

“;It's definitely going to be a challenge for us,”; Hawaii coach Mike Trapasso said. “;I don't know what to expect going into this weekend with five games and one of our best guys down.”;

Hawaii (10-6) will try to extend its seven-game winning streak against Washington in the first game of a doubleheader tomorrow at 9 a.m. Senior Jayson Kramer (1-2, 3.54), who threw more than 100 pitches in 72/3 innings last week against LMU, will start.

Hawaii will then turn to Jared Alexander (0-0, 0.00) against host Portland in the second game at 12:30 p.m.

Alexander, who has slowly made his way back from an arm injury, hasn't allowed an earned run in 13 innings this season.

But he's coming off his toughest outing of the season, where he struggled through five innings, allowing four hits, three unearned runs and two walks.

“;That's probably the worst we'll see him pitch this year,”; Trapasso said. “;As far as the fastball command, he really struggled.”;

Alexander, who has been on a fairly strict pitch count since his return, fatigued in his last outing as he got up to the 75-pitch mark.

“;The normal next step for Jared is 90 pitches. We may keep him closer to 75-80,”; Trapasso said. “;I'd rather not jump up to the next level until he shows really a comfort level at what the pitch count was previously.”;

Freshman Matt Sisto (1-1, 5.03) will start Saturday's game against Oregon, leaving the tournament finale Sunday, whether it be the consolation or championship game, in the hands of freshman Connor Little (1-0, 2.16), who will make his first collegiate start.

“;It's going to be interesting, but he deserves the next start,”; Trapasso said. “;I think it'd be unrealistic (to go seven innings) because he hasn't really done it, but that's the challenge that comes with Klein being down. We just need him to go out and throw strikes.”;

In 16 games this season, Hawaii's starting pitcher has earned the win just twice. But they've kept the Rainbows in games, allowing relievers Sam Spangler, Josh Slaats and Harrison Kuroda to combine for seven wins, and given the offense a chance to score late.

That's how the Rainbows swept LMU last weekend, scoring the go-ahead or wining runs after the sixth inning in all four games.

“;Our starting pitching has been real good,”; Trapasso said. “;In fact, they've almost overachieved these first 16 games.”;

Kolten Wong exploded in a big way Sunday, becoming the fifth Rainbow to hit three home runs in a game in a 6-5 win over the Lions.

But the Rainbows were fortunate to pull out one win against LMU with only two hits, and only had four hits other than Wong's three homers on Sunday.

Currently they're hitting .250 as a team and Vinnie Catricala (.362) is the only regular hitting over .290.

“;We need to be more consistent,”; Trapasso said. “;We've got to get everybody up and down the lineup hitting.”;

Hawaii finishes its road trip with a game at Oregon State on Monday that the 'Bows will staff. Then it'll return home for a four-game series against Coastal Carolina before opening Western Athletic Conference play April 3 against San Jose State.