Orioles-Red Sox Preview

Knocking a quality starting pitcher out of the game is usually a good thing.

With the way the Orioles bullpen is performing, the Boston Red Sox may not be in the mood to face any more Baltimore relievers.

Before the bullpens factor in Saturday's game at Fenway Park, the Red Sox will send Aaron Cook to the mound to make his debut with the club against Baltimore's Jason Hammel in a matchup with a decidedly Rocky Mountain flavor.

Boston (11-14) plated four runs in five innings off Orioles starter Wei-Yin Chen in Friday's series opener, but five Baltimore relievers shut the Red Sox down from there, limiting them to three hits over eight scoreless innings. Baltimore (17-9) finally won it 6-4 in the 13th after Chris Davis had an RBI single and Mark Reynolds added a sacrifice fly.

The relief corps is perhaps the biggest reason why the Orioles - winners of three straight and nine of 11 - have emerged as one of baseball's most pleasant early-season surprises. With a collective ERA of 1.56, Baltimore's bullpen is the only one in the majors with a mark below two. Orioles relievers have thrown 18 2-3 consecutive scoreless innings, allowing six hits and a .100 opponent batting average during that run.

"As a defense that's all you ask for. It's a pitching staff that's going to go after the hitters and let us work,'' center fielder Adam Jones said. "The starting pitching has been outstanding. The bullpen, if there's a word better than outstanding, that's what they've been."

Acquired from Colorado in February's Jeremy Guthrie trade, Hammel (3-1, 1.97 ERA) has been nearly as dominant for Baltimore as the relievers. The right-hander has allowed two runs or fewer in each of his five starts, but got charged with his first loss Monday at New York, yielding two runs over six innings of a 2-1 defeat.

Despite that outcome, Hammel became the first Orioles pitcher with a minimum of four April starts to post an ERA under two since 1989, when Jeff Ballard opened 5-0 with a 1.46 ERA.

Hammel spent the last three seasons in the Rockies rotation alongside Cook, whom the Red Sox summoned from Triple-A Pawtucket on Thursday - five days before he could have opted out of the minor league contract he signed in January.

The sinkerballer, who spent his first 10 years in the majors with Colorado, is making a spot start in place of Josh Beckett (sore right lat muscle). Cook endured the worst season of his career in 2011, going 3-10 with a 6.03 ERA after missing the first two months with a fractured right hand. He looked excellent at Pawtucket this spring, though, going 3-0 with a 1.89 ERA in four starts.

"I don't think there's any need to really project anything further than this Saturday. We'd like to see him in a Red Sox uniform in the big leagues and take it from there," Red Sox manager Bobby Valentine told the team's official website.

Boston slugger David Ortiz is 6 for 10 with a homer off Hammel, while Dustin Pedroia is 3 for 4 with a home run and a double.

The Red Sox have dropped three straight and eight of their last nine at Fenway, where they are 4-8 on the season for their worst home start since 1996. Boston hasn't opened 4-9 at Fenway since 1984.

"Everyone wants to play well at home, but we haven't. We've got to figure out how to do that,'' Pedroia said.