The Los Angeles Angels of Anaheim need a big effort from Garrett Richards tonight when they kick off a four-game set with the Baltimore Orioles at Angel Stadium.

With Dan Haren set to have his back checked out, Jerome Williams already on the disabled list and a bullpen that is taxed thanks to an awful showing from Ervin Santana in Wednesday's 12-3 loss to Cleveland, Richards needs to bounce back from a poor showing of his own his last time out.

Richards suffered his first loss of the season on Saturday in Toronto and allowed 10 runs (5 earned) and nine hits with four walks in 4 1/3 innings to drop him to 2-1, while raising his ERA more than a run to 2.81.

"It was just one of those days," Richards said. "I was throwing some good sliders, but I just wasn't getting the swings and misses that I usually do. Four-seam was good, two-seam I thought I had decent control over, but nothing more I can say. Just one of those days. Everybody was off."

Whether Richards has his stuff tonight or not, he may be needed to go big innings for the Angels, who have seen their bullpen throw 10 1/3 innings the past two games.

In Wednesday's loss to the Tribe, Santana (4-9) was rocked for eight runs on six hits and three walks in just 1 1/3 innings -- his shortest outing of the season.

"It was obviously a rough outing," Angels manager Mike Scioscia said of Santana's effort. "He had a nice delivery, just couldn't get his fastball in a good zone."

Maicer Izturis drove in a pair of runs and Alberto Callaspo added an RBI with a sacrifice fly for the Angels, who have dropped four of their last six games.

Baltimore, meanwhile, got a huge lift from Chris Tillman on Wednesday, as he pitched into the ninth inning to help the Orioles get past the Seattle Mariners, 4-2, in the rubber match of a three-game series at Safeco Field.

It was the first start of the season for Tillman (1-0), who was recalled from Triple-A Norfolk prior to the game. He was charged with two unearned runs on two hits with two walks and seven strikeouts in a career-high 8 1/3 innings.

"Oh, he was great," said Orioles manager Buck Showalter. "He handled the fastball; curveball was a big pitch for him. Got the change up going later in the game just to give a different wrinkle. Frustrating he couldn't finish it off because he had the stuff to pitch a complete game today."

Adam Jones homered for Baltimore, which won two straight to end the series following a three-game slide.

Getting the call for the O's tonight will be righty Jake Arrieta, who is 3-9 with a 5.81 ERA. Arrieta did not get a decision on Friday against Cleveland, as he allowed five runs and eight hits in only 3 2/3 innings of his team's 9-8 win.

Arrieta, who has just one win in his last 11 starts (1-7), lost to the Angels earlier in the year and has pitched to a 5.25 ERA in two starts against them.

The Angels won two of three at home against the O's on April 20-22 before sweeping a pair in Baltimore on June 26-27.