The Athletics lost Grant Balfour to free agency this offseason, but they still beefed up their bullpen with the Luke Gregerson, Eric O'Flaherty and Jim Johnson acquisitions. That relief depth will be tested early in camp because two of the club's setup men are already dealing with injury problems. Compete in a 10-team Fantasy Baseball league for a chance to win up to $5,000. Join a Prize League now! EyeOn Baseball A's Ryan Cook (shoulder), Sean Doolittle (calf) delayed by injury By Mike Axisa | Baseball Writer February 14, 2014 3:44 pm ET Both Ryan Cook (left) and Sean Doolittle are dealing with injuries early in camp.Both Ryan Cook (left) and Sean Doolittle are dealing with injuries early in camp. (USATSI) MORE: FA tracker: position players | FA tracker: pitchers The Athletics lost Grant Balfour to free agency this offseason, but they still beefed up their bullpen with the Luke Gregerson, Eric O'Flaherty and Jim Johnson acquisitions. That relief depth will be tested early in camp because two of the club's setup men are already dealing with injury problems: Ryan Cook, 26, had a 2.54 ERA (147 ERA+) in 67 1/3 innings last season. Since coming over from the Diamondbacks in the Trevor Cahill trade, the right-hander has a 2.30 ERA (166 ERA+) with a 1.11 WHIP and 9.4 K/9 in 140 2/3 innings for Oakland. Sean Doolittle, a 27-year-old southpaw, had a 3.13 ERA (119 ERA+) in 69 innings last summer. The former first baseman has pitched to a 3.09 ERA (123 ERA+) with a 1.01 WHIP and 9.3 K/9 in 116 1/3 innings since being called up in early 2012.