SEATTLE -- The Rangers have activated Scott Feldman off the disabled list after he declined their request for him to continue pitching as a starter at Triple-A Round Rock.

Instead Feldman, whose 30-day rehabilitation assignment expired right before the All-Star break, will pitch out of the Rangers' bullpen as their long man. To make room for him, the Rangers optioned pitcher Darren O'Day to Round Rock. They also designated pitcher Zach Phillips for assignment to make room on the 40-man roster.

The Rangers put Feldman on outright waivers and he cleared, but did not want to go to the Minor Leagues. That forced the Rangers to either activate Feldman or release him.

"The latter wasn't an option," Rangers general manager Jon Daniels said. "We had prioritized him to continue to start rather than a long role in the bullpen. We approached him with that, and it was his right to make the call. He has worked hard to come back from injury, it has been a long road and he wanted to contribute any way he could."

O'Day had a 1.94 ERA in 140 relief appearances over the past two years, but has struggled to regain that effectiveness. He had a 2.45 ERA in April before undergoing surgery to repair a torn labrum in his left hip. He missed over two months and has not been effective since coming back. In three outings, he has allowed three runs on five hits in 3 1/3 innings.

The Rangers want him to go to Round Rock and get regular work.

"We think Darren could benefit from pitching on a regular basis with the nature of his injury," Daniels said. "That's hard to do at the Major League level when everything is dictated by game situations and how long a starter goes. If he gets on a roll, we'd definitely love to get him back. He has been one of our more effective pitchers the last few years."

Feldman was the Rangers Pitcher of the Year in 2009, when he went 17-8 with a 4.08 ERA. But he slipped to 7-11 with a 5.48 ERA last season and was shut down at the end of the year because of a knee injury that ultimately required surgery. He has been on the disabled list since the beginning of Spring Training and was 3-1 with a 4.17 ERA in in 10 games in the Minor Leagues.

He was 1-0 with a 1.89 ERA in four starts in June, but has allowed 12 runs on 17 hits over 10 innings in his past two starts for Round Rock.

"The reports have been good," Daniels said. "He's progressively getting more movement, his velocity is better and his knee has bounced back. As evidenced by his decision, he's got confidence he can help us up here."

The Rangers don't have a spot in the rotation open with C.J. Wilson, Colby Lewis, Matt Harrison, Alexi Ogando and Derek Holland. But they are concerned about their depth right now if something happens to one of those five at some point. That's why they wanted Feldman to continue starting at Round Rock.

"We'd rather have a sixth starter than a long guy," Daniels said. "This doesn't preclude Scott jumping into the rotation at some point, but we wanted to keep him stretched out."

Tommy Hunter also stays in the bullpen. He was 22-10 with a 3.91 ERA in 41 starts for the Rangers over the past two years, and they could have optioned him to Round Rock. That would have allowed him to be stretched out as a starter. But the Rangers want him in the Major League bullpen.

"We feel he is being used in an important role right now," Daniels said. "He has looked down. We didn't feel [sending him to the Minors] was the right move."

The Rangers are still looking for relief help and remain in discussions with other teams.

"If there is a way to improve the ballclub, we will, but the bullpen is still our focal point," Daniels said. "If there is an opportunity to improve the club, we will look at it."

The Rangers remain concerned about their rotation depth. The Round Rock rotation currently consists of Derek Hankins (5-6, 6.37), Eric Hurley (2-0, 4.91), Neil Ramirez (4-3, 3.77), Zach Jackson (6-3, 5.59) and Martin Perez, who was promoted from Double-A Frisco on Thursday.

Hurley has had a number of physical setbacks this season and missed the past two years with injuries. But Daniels said he has progressed to the point where he could be an option at the Major League level.