Ryan Cook left Wednesday's game against the Mariners with a right forearm strain.

It's bad news for the reliever, who dealt with shoulder issues to start the year. He's likely looking at a return trip to the disabled list.

Ryan Cook left the first game of Wednesday's doubleheader against the Mariners with an undisclosed injury.

Cook came on in the top of the 10th inning and faced four batters, leaving with runners on the corners and two outs. Cook's replacement, Daniel Otero, immediately allowed the inherited runner to score, adding insult to the not-so-proverbial injury. More on Cook's status should be known shortly.

Athletics manager Bob Melvin confirmed Friday that he's still planning on using a closer by committee in the ninth inning, but that Ryan Cook is not yet a part of that mix.

Cook is working his way back from a right shoulder strain, having just been activated off the disabled list on Monday. Luke Gregerson, Sean Doolittle and Dan Otero are expected to share chances in the ninth inning for the time being.

A's manager Bob Melvin said Thursday that he plans to use a committee at closer.

Jim Johnson was demoted from the ninth-inning role after yet another poor outing on Wednesday. The committee will be made up of Ryan Cook, Luke Gregerson, Dan Otero, and Sean Doolittle. Cook profiles best as a closer out of that group, but he was just activated from the 15-day disabled list on Monday.

Athletics activated RHP Ryan Cook from the 15-day disabled list.

Cook will join the A's bullpen on Monday. He battled a right shoulder strain this spring but is fully healthy now and should step right into a setup role. The right-hander is a decent fantasy stash with Oakland closer Jim Johnson experiencing early-season struggles.

Ryan Cook (shoulder) threw a successful simulated game Monday.

Cook has been nursing a right shoulder strain since early on in spring training, but it doesn't appear he's that far away from returning. He's eligible to be activated on Saturday and is seems like he should be ready then or shortly after.

Athletics placed RHP Ryan Cook on the 15-day disabled list, retroactive to March 21, due to a right shoulder strain.

The issue is believed to be minor, and with the backdated DL stint, Cook is eligible to return to the A's bullpen as early as April 5. Luke Gregerson will function as the primary setup option until his return.

Ryan Cook (shoulder) will start the season on the disabled list, A's manager Bob Melvin said Sunday.

Cook has been working back from shoulder inflammation, and the few days he's behind are enough to keep him off the Opening Day roster. Cook won't pitch in another game this spring, though, so he'll be eligible to come off on April 5. He should be back pitching in O.co Coliseum in short order.

Ryan Cook threw 17 pitches in a minor league game on Saturday.

The right-hander registered four outs with his 17 pitches, including two strikeouts. Cook still has a few days to get into game shape before Opening Day after shoulder inflammation set him back earlier in spring. With each successful outing it's becoming more and more likely he'll be ready to go for the opener.

Ryan Cook (shoulder) believes he'll make his spring debut on Saturday.

Cook successfully completed a 21-pitch bullpen session on Wednesday and game action is next up on the docket. Oakland has eased Cook into action because of shoulder inflammation. The right-hander would seem to be about a 50/50 proposition to begin the season on the disabled list.

Ryan Cook (shoulder) is scheduled to make an appearance in a simulated game on Thursday.

Cook threw live batting practice on Sunday in A's camp and reported no issues. He has been taking it easy this spring because of shoulder inflammation, but the right-hander should be ready to join the A's bullpen by mid-April. He's expected to serve as the primary setup man to new Oakland closer Jim Johnson.

Ryan Cook (shoulder) will throw live batting practice Sunday.

It's the first time he's done so since showing up with shoulder inflammation. Cook has made some nice progress and seems likely to appear in games soon, but he's not expected to be ready for the start of the season.

Ryan Cook (shoulder) said after a 20-pitch bullpen session Thursday that it's the "best I've felt" all spring.

Cook has been limited in camp since showing up with shoulder inflammation, but he's been throwing off a mound for a week now and is progressing steadily. The A's reliever is running out of time but remains optimistic he can get ready for Opening Day. It's not clear when he'll first appear in Cactus League action.

Ryan Cook (shoulder) said Saturday that he felt great after his second spring bullpen session.

Cook was able to ramp up to full velocity for the first time this spring, and noted that his shoulder felt fine before and after the session. The hard-throwing 26-year-old is expected to work in a setup capacity in front of new closer Jim Johnson.

Ryan Cook (shoulder) threw his first bullpen session of the spring on Thursday in A's camp.

Cook made 20 throws and reported feeling fine. He had some inflammation in his right shoulder in February but should be able to get on track rather quickly. The talented 26-year-old right-hander is probably next in line for saves in Oakland behind new closer Jim Johnson.

Ryan Cook (shoulder) is scheduled to throw a bullpen session on Thursday in A's camp.

Cook has been dealing with shoulder inflammation since early February. "It's going to be close as far as Opening Day," manager Bob Melvin acknowledged Monday morning.

Ryan Cook (shoulder) threw from flat ground with no issues Thursday and remains on track to return to the mound early next week.

Cook has dealt with shoulder inflammation since the beginning of camp, but it's pretty much a non-issue at this point. The setup man will have no trouble getting ready for Opening Day as long as he can avoid setbacks.

Ryan Cook (shoulder) is scheduled to throw off flat ground Thursday and Saturday.

Cook showed up to camp with shoulder inflammation, but he should be able to get back on the mound if there are no issues in his upcoming throwing sessions. He should only need a handful of appearances before Opening Day, so the A's will continue to play things safe.

Ryan Cook (shoulder) could throw a bullpen session before the end of the week.

"We're getting close," A's manager Bob Melvin said. "I don't want to get too far ahead of myself, but yes, potentially this week." Melvin added that Cook has "felt great for a while," but the club obviously wants to proceed cautiously with their setup man. He still has plenty of time to be ready for Opening Day.

Ryan Cook (shoulder) has scaled his throwing back from 105 feet to 90 feet, but has increased his velocity as he works has way back from stiffness in his right shoulder.

Cook admittedly isn't worried about the shoulder inflammation, and shouldn't have any trouble getting himself ready and in game shape in time for Opening Day. He'll be one of many quality setup men available in the A's bullpen to get the ball to closer Jim Johnson.