SEATTLE -- After much trial and error, Rangers manager Ron Washington believes he finally has defined roles for the seven pitchers in his bullpen. That was not always the case in the first half, but the emergence of Mark Lowe and Tommy Hunter as the right-handed setup relievers has allowed Washington to put his bullpen in order.

Neftali Feliz remains the closer, Lowe is the eighth-inning right-handed setup reliever and Hunter will likely work the sixth and seventh. Hunter can pitch multiple innings while Washington would like to limit Lowe to one.

Darren Oliver will be the left-handed late-inning reliever while Arthur Rhodes will likely be used in matchup situations against left-handed hitters. Rhodes has not allowed a run in his last nine appearances covering 6 2/3 innings. Left-handed hitters are batting .212 off him, while right-handers are hitting .347.

Yoshinori Tateyama will be used in middle relief and in matchup situations against right-handed hitters. Right-handed hitters are batting .205 off him, as opposed to .303 by left-handers. Scott Feldman will be the Rangers' long reliever, used in a similar manner as David Bush early in the season.

The Rangers' biggest concern has been identifying a dependable right-handed setup reliever. But Lowe has seized that job with a 3.12 ERA in his last 10 outings. He has allowed runs in just two of those ten outings.

Borbon considering ankle surgery

SEATTLE -- Rangers outfielder Julio Borbon, on the disabled list at Triple-A Round Rock with a sprained left ankle, is considering the possibility of surgery. That would likely sideline him for six to eight weeks.

Borbon fractured his ankle in 2007 during his junior year at Tennessee. The injury also resulted in some ligament damage and surgery would help strengthen his joint. Nothing has been decided.

"He's looking at some options," general manager Jon Daniels said. "Right now he is getting treatment. But having injured it a couple of times and being a speed player, he wants to make sure the ankle is good and strong."

Borbon was the Rangers' Opening Day center fielder but went on the disabled list with a strained left hamstring on May 14. He was removed from the disabled list on June 3 but sent to Round Rock because the Rangers liked the production they were getting from Endy Chavez.

Chavez and Craig Gentry have formed a platoon partnership in center field. Chavez went into the second half hitting .330 with 21 runs scored, three home runs and 12 RBIs over 33 games and 106 at-bats. Gentry, who has shown to be a standout defensive player, was hitting .257 in 33 games but is batting .316 since the beginning of June. The Rangers also have David Murphy.

"They have been doing a good job," Daniels said. "It gives [manager Ron Washington] some options and he's able to keep guys fresh. Ron has done a good job getting contributions from everybody."

If the Rangers need help in center field, Leonys Martin could be considered. A Cuban defector who signed with the Rangers earlier this season, Martin was recently promoted to Round Rock after hitting .348 in 29 games at Double-A Frisco.

"I'm hoping we don't have a need, but he is in Triple-A and on the roster," Daniels said. "If there is a need, it would be something we'd talk about."

Feldman chooses bullpen over Minors rotation

SEATTLE -- Scott Feldman still wants to be a starting pitcher. But the Rangers don't have a spot for him in their rotation right now, so he told them he would rather be a reliever in the Major Leagues rather than a starter in the Minors.

Feldman was activated off the disabled list on Thursday. The Rangers wanted to outright him to Triple-A Round Rock so he could remains stretched out as a starter, but Feldman had the right to reject that. He did so, telling the Rangers on Wednesday night after he cleared outright waivers.

"I'd rather help the team," Feldman said. "I've been away so long, it's nice to get back here. Hopefully I can stay stretched out if they need me to change roles. If I was able to pick a role, I would rather starter. But I would rather be in the big leagues than the Minor Leagues."

Feldman has done both in his career. He is 28-27 with a 4.73 ERA in 78 career starts and 3-5 with a 5.08 ERA in 86 relief appearances.

Perez promoted to Triple-A

SEATTLE -- Left-handed Rangers pitching prospect Martin Perez, coming off his one inning of work in Sunday's All-Star Futures Game, has been promoted from Double-A Frisco to Triple-A Round Rock.

Perez, 20, was 4-2 with a 3.16 ERA in 16 starts and one relief appearance at Frisco. He was 5-8 with a 5.96 ERA at Frisco in 2010 and is the Rangers' No. 1 ranked prospect by MLB.com.

"He has shown consistency in the strike zone and he's got three pitches that are all above average," Rangers general manager Jon Daniels said. "His command, especially in the lower half of the strike zone, is a lot better. He has been [in Frisco] a year and a half. It's time for a new challenge. He has done what we've asked him to do at Double-A."

As far as being an option at the Major League level, the Rangers would prefer Perez get a few starts at Triple-A before they consider that.

Worth noting

• Saturday's start against the Mariners has been pushed back to 9:15 p.m. CT due to pregame ceremonies at Safeco Field.

• The Rangers used just six starting pitchers in the first half. They used seven last season. The fewest was five in 1984: Danny Darwin, Charlie Hough, Frank Tanana, Dave Stewart and Mike Mason. The last time they used just six before the break was in '96: Ken Hill, Darren Oliver, Roger Pavlik, Bobby Witt, Kevin Gross and Rick Helling.