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3/18/2014 8:33 P.M. ET

With rotation set, three 'pen roles up for grabs

GLENDALE, Ariz. -- Oakland's rotation is firmly set, barring another ill-fated injury, but the club still has several bullpen decisions to make in advance of Opening Day.

As expected, manager Bob Melvin confirmed Tuesday that Jesse Chavez and Tommy Milone will replace injured hurlers Jarrod Parker and A.J. Griffin in a rotation that already includes Sonny Gray, Scott Kazmir and Dan Straily.

With Chavez's late spring emergence in a starting role, the A's will have to replace him in the bullpen. They are also preparing to potentially enter the season without righty setup man Ryan Cook, who has yet to appear in a spring game after a bout with shoulder inflammation. He'll throw in a simulated game on Thursday.

Add in another open bullpen spot, and that's three up for grabs next to closer Jim Johnson and fellow relievers Luke Gregerson, Sean Doolittle and Dan Otero, all locks. Lefty Fernando Abad likely gets one of them, and right-hander Evan Scribner is a good bet for another in a long-relief role.

The A's would still need one more reliever from the group of Drew Pomeranz, Josh Lindblom, Joe Savery and Arnold Leon. Pomeranz will be stretched out to start, so expect him to begin the season at Triple-A Sacramento to provide rotation depth. Leon, too, will be stretched out, and the A's will also attempt to do the same with Savery. Lindblom, who also has the ability to both start and relieve, seemingly has the edge.

The right-hander, acquired in the Craig Gentry deal that sent Michael Choice to Texas, has allowed five runs on 14 hits in 11 spring innings for a 4.09 ERA, walking three and fanning eight.

"Depending on the Cook situation, it may turn out that we have a guy at the big league level that we're looking to stretch out even more," said Melvin. "It's also tough to do. Jesse was pretty unique being able to do that. If you needed him to give you six innings in a particular game, he's able to do that. He's been a starter before and has the unique ability to sit around for a while and still do that for you. We'll see if we have anyone else who's able to do that type of thing."

Kazmir slated to take the hill Saturday

GLENDALE, Ariz. -- Lefty Scott Kazmir, scratched from his Monday start with minor triceps tightness, will be back on the mound in a game on Saturday.

This allows the A's to essentially skip him one turn and give him additional rest. In between, he'll throw a bullpen.

"He feels good," manager Bob Melvin said. "He was wanting to pitch today."

By pitching him Saturday, the A's keep Kazmir on the same throwing schedule, meaning he's still in line to start behind projected Opening Day man Sonny Gray when the season begins.

Kazmir has yet to give up a run in seven innings over two starts this spring.

After earning rotation spot, Chavez impresses Melvin

GLENDALE, Ariz. -- Jesse Chavez has already earned a rotation spot. Just don't tell him that.

"All I've told him is what I expect out of him," said manager Bob Melvin, "but he's not taking anything for granted, and that's good."

"It's just been hearsay to me, and I haven't approached it as, 'I'm in the rotation,'" Chavez said. "I've approached it like I'm just showing up every five days to get my work in and get ready for the season.

"It's awesome to be considered for it and to hear it."

Oakland's decision to move Chavez from the bullpen to the rotation, in the wake of injuries to Jarrod Parker and A.J. Griffin, looked good yet again Tuesday, when the right-hander limited the White Sox to a pair of runs -- both coming on solo shots -- in 4 2/3 innings. He allowed six hits and walked two with two strikeouts.

Conor Gillaspie's second-inning homer off Chavez ended the hurler's spring streak of 14 scoreless innings. He exited the game with a 1.04 Cactus League ERA.

"He was good again, real good," said Melvin. "You can see him out there grinding. He throws one bad pitch or gives up a hit, he's upset. He's got high expectations for himself. He wants to keep pitching in this fashion, and even in a game like that, when it's tough to keep your focus at times, he seems like he's on it every pitch, so he continues to impress."

Chavez is on track to slot into the rotation between Scott Kazmir and Dan Straily, and his anticipated season debut on April 2 will mark his first starting assignment since June 24, 2012.

"I'm fine with it," he said, smiling. "I like it, it's fun. It just gives me more confidence that they have confidence I can do it. I'm going to try to ride that wave of confidence."

Worth noting

• Righty reliever Fernando Rodriguez will throw in a Minor League game on Friday, which will mark his first time pitching in a non-simulated game since undergoing Tommy John surgery.

• Melvin said he will wait to announce an Opening Day starter for at least a few more days.

"I think after these next starts, we'll have a better idea of how we line things up," he said.

Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.