SURPRISE, Ariz. -- Outfielder Josh Hamilton met with manager Ron Washington on Saturday afternoon to discuss his tight groin muscle. Hamilton started in center field on Friday night against the Rockies and had to come out of the game after seven innings because of the tightness.

Hamilton wanted to reassure his manager that injury had nothing to do with playing center field. Hamilton told Washington that he first felt the muscle grab at him while running the bases. Washington, who has expressed concerns in the past about the wear and tear on Hamilton's body playing center field, accepted the explanation.

"He told me he didn't get hurt playing center and I told him I understood," Washington said.

Craig Gentry, who is likely going to make the Rangers as the fourth outfielder, started in center field on Saturday night. Gentry was 1-for-3 with a walk on Friday and is hitting .152 (5-for-33) on the spring.

The Rangers are trying to do everything they can to get him ready for Opening Day. The Rangers need his right-handed bat as a complement to David Murphy, a left-handed hitter who is going to get a chance to play regularly in left field.

That leaves one spot on the bench that's down to Julio Borbon or Brandon Snyder, although the Rangers continue to look for a right-handed hitting outfielder in the waning days of Spring Training.

Kirkman impresses, optioned to Triple-A

SURPRISE, Ariz. -- Left-handed reliever Michael Kirkman, who emerged early in camp as a strong candidate for the bullpen, was optioned to Triple-A Round Rock on Saturday. That leaves rookie Robbie Ross and veteran Neal Cotts as the prime left-handed candidates still in camp.

Kirkman pitched 13 1/3 innings over nine games and allowed 10 earned runs on 18 hits and three walks with nine strikeouts.

"He certainly showed a lot of improvement in his ability to keep the ball in the strike zone," Rangers manager Ron Washington said. "The other two left-handers just pitched better. We still have a high opinion of Kirkman. We hope he goes to Round Rock, gets his innings in and competes. We know where he is. He has improved a lot, the other pitchers have pitched a little better."

Ross and Cotts are competing with right-hander Yoshinori Tateyama for a spot in the bullpen. Ross, 22, who was 10-5 with a 2.34 ERA in 27 games at Class-A Myrtle Beach and Double-A Frisco last season, pitched two more scoreless innings in the Rangers 5-3 victory over the Rockies on Friday night and has a 1.64 ERA for the spring. Opponents are hitting .250 off him.

He and Cotts have been the two biggest surprises in camp. Cotts hasn't pitched in the Major Leagues since 2009, having undergone one elbow surgery and four hip operations since then. He was signed at the beginning of camp to a Minor League contract with almost no chance to make the team. But he has not allowed a run in his last three outings and the Rangers are wondering if he can pitch his way back to his former level as a left-handed setup reliever.

"His arm is healthy and his hip is healthy," Washington said. "The ball is coming out of his hand real well. The more opportunities he's had, the better he has been. He's got experience. He has been pitching well enough to be in the running. We're trying to push it as far as we can to make sure we make the right decision."

If Ross does not make the bullpen, he'll be used as a starter at Triple-A Round Rock as soon as he gets stretched back out.

Reynolds, Scheppers sent to Round Rock

SURPRISE, Ariz. -- The Rangers have sent pitchers Greg Reynolds and Tanner Scheppers to Triple-A Round Rock. Reynolds will be used in the Round Rock rotation while Scheppers will pitch out of the bullpen.

Reynolds has made a major impression on the Rangers this spring after being acquired from the Rockies this winter for infielder Chad Tracy. He had a 3.75 ERA in four outings this spring and opponents hit .205 off him. He had one walk and nine hits against eight strikeouts in 12 innings pitched.

"Very impressive," Rangers manager Ron Washington said. "I didn't know anything about him but he made an impression. He has made some changes in his delivery and it has paid off."

Reynolds was the second overall pick out of the 2006 First-Year Player Draft by the Rockies. His career was set back by a variety of injuries and he split time between Triple-A and the Rockies last season. He was 3-0 with a 6.19 ERA in three starts and 10 relief appearances for the Rockies last season.

He will pitch in a Round Rock rotation that will also include left-hander Martin Perez. Other Round Rock rotation candidates include Neil Ramirez, Derek Hankins and Mark Hamburger but it won't be finalized until the Rangers make a decision on Robbie Ross.

Beltre continues to rest stiff lower back

SURPRISE, Ariz. -- Rangers third baseman Adrian Beltre was out of the lineup on Saturday with mild stiffness in his lower back. He has not played since Wednesday and is questionable for the Cactus League finale on Sunday against the Padres.

"It's not considered significant but it's something we're trying to knock out before we go back," assistant general manager Thad Levine said. "He has had this in past Spring Trainings because of the pounding and the workload, and we don't want it to linger."

Beltre has played in 18 games and is 13-for-50 (.260) with three doubles, no home runs and 11 RBIs. He is 5-for-12 with three doubles in his past three games.

Outfielder David Murphy was back in the lineup on Saturday. He missed Friday's game with a mild case of food poisoning.

Worth noting

• The Rangers have returned catchers Luis Martinez and Dusty Brown to the Minor Leagues. They will do the catching for the Rangers at Triple-A Round Rock. Tommy Mendonca will also be at Round Rock but will see most of his action at third base with only occasional action behind the plate.

• The Rangers still haven't made a call on their utility infielder spot with Alberto Gonzalez and Luis Hernandez still in camp.

• Mike Adams pitched in a Minor League intrasquad game on Saturday. He walked one and struck out two. The other out came on a caught stealing.

• The Rangers traded outfielder Kyle Hudson to Tampa Bay for future considerations. Hudson was signed this offseason as a center fielder to a Minor League contract but the Rangers don't have room for him at Triple-A. Leonys Martin is playing center field at Triple-A and there is a possibility that Julio Borbon could start the season at Round Rock. Prior to this, the Rangers had never made a trade with Tampa Bay.