Coming off two strong starts, senior right-hander Justin Costi will start the third game of this weekend's Western Athletic Conference series against Louisiana Tech.

Costi (2-0, 5.94 earned run average) will pitch in Sunday's series finale in the spot left-hander Mark Rodrigues (2-1, 3.99) had started six times.

"He's been good the last couple starts, staying within himself, throwing three pitches for strikes," UH coach Mike Trapasso said of Costi. "He's showing a little more pitchability.

"(But) Mark's still a guy who's going to be huge for us. He's had two or three starts where he's struggled being consistent in the zone and with his off-speed pitches."

Rodrigues will be used out of the bullpen and, depending on how he is used in the series, he will likely start one of the midweek games at UH-Hilo next week, Trapasso said.

Steven Wright (4-1, 2.40) and Ian Harrington (3-1, 3.38) will start tomorrow and Saturday, respectively, for UH, which owns a 13-11 lead in the series.

That the Rainbows (18-6) are able to make such a move is a credit to their pitching depth. This will be Costi's fifth start of the season. After struggling his first two starts against San Diego State and Hawai'i Pacific — he allowed 10 runs in 5 2/3 innings combined — he won his last two starts, beating Washington, 10-6, and Western Illinois, 3-0, in a rain-shortened 4 1/2-inning game Monday. In those two starts, he has allowed one run, seven hits and two walks with nine strikeouts.

"It gives ourselves the opportunity to give a guy a chance that might be going best at the time," Trapasso said. "But it all could change next week."

Meanwhile, Louisiana Tech (9-10) has won five of its last eight since getting swept in three at No. 10 Arkansas, winner of the Rainbow Tournament several weeks ago. The Bulldogs beat Baylor, 12-4, at the Bears' tournament over the weekend, yet they split a doubleheader with Lamar on Tuesday.

The Bulldogs average 8.4 runs per game and have a team batting average of .322.

"I think they're the hottest team in our league the way they've been playing the last couple of games," Trapasso said.

The Rainbows, coming off a five-game sweep of Western Illinois, are on a roll themselves. But Trapasso must trim his roster to 25 for conference play. It won't be easy.

"This will be our toughest decision to make thus far from a roster stand point," he said. "I haven't done it yet. You can wait until the lineup exchange (with the umpires and opposing coach). There might be a couple guys left off who have done well in the non-conference games."

The Rainbows' depth has been tested with injuries early in the season. The infield will be without Jon Hee (subluxed left shoulder).

Still, UH can still go two deep in the infield without Hee, who played third and second. Justin Frash, Adam Roberts and Joe Spiers have played third; Spiers, Eli Christensen and Nathan Young have played shortstop; Spiers and Christensen have played second, and Luis Avila and Kris Sanchez have played first base.

Matt Inouye started two games at catcher against WIU, solidifying depth behind the plate with Esteban Lopez doing the bulk of the work.

The outfield also is deep with Inouye in right, Robbie Wilder in center or left, Jorge Franco in left or right and Derek DuPree in center.

Since WAC series are three games, the Rainbows have depth in the bullpen. Darrell Fisherbaugh (four saves), Rich Olsen (one save), Rodrigues, Matt Daly, Keahi Rawlins and Tyler Davis (one save) are more than enough relief, as UH starters have not reached the fifth inning only five times this season.

Reach Stacy Kaneshiro at skaneshiro@honoluluadvertiser.com.