ARLINGTON -- Rangers outfielder Shin-Soo Choo turned 37 on Saturday, but he doesn’t feel that old and his play this season reinforces that.

For the second straight game, Choo got Texas going with a leadoff home run, although the Rangers went on to lose, 7-6, in 11 innings. Saturday's was against left-hander Wade Miley and was down the left-field line. On Friday, Choo took right-hander Gerrit Cole deep.

“I’m 37, but honestly, I probably feel like I am 29 or 30,” Choo said. “My body may not feel like it used to, but I still take care of myself. Before, I would stop by the training room only when I was hurt. Now, I stop by to keep getting treatment and help me to prepare for the game every day.”

Choo entered Saturday’s game against the Astros slashing .294/.389/.505, and his .894 OPS ranked ninth among qualified hitters in the American League. That mark would be the second highest of Choo's career and highest since 2008.

“He is probably having his best [season] at age 37,” Rangers manager Chris Woodward said. “Pretty amazing. It speaks volumes about how hard he works. He is consistently trying to improve, and his regimen is as good as I’ve ever seen. He has a healthy fear of somebody coming up behind him and taking his job.”

Choo’s age vs. production is a significant factor. He is signed through 2020, which will be the final season of his seven-year, $130 million contract. Aside from injuries, Choo has done pretty much what would have been expected from him through the contract, and he is in position to finish strong.

Choo has also successfully fought off the perception that he needs to be used strictly as a designated hitter. He has played 30 of his 86 games this season in the outfield.

“I go out every day and do my sprints,” Choo said. “I’m not getting faster, but I want to keep my speed. I want to be able to score from second base on a single. I don’t want them to think they need to use a pinch-runner.”

Choo’s best work has been in the first inning, as evidence of his homer off Miley. He is hitting .465 with a .542 on-base percentage and an .859 slugging percentage in the opening frame this season.

“The only difference in the first inning is if they throw me a first pitch for a strike, I’m swinging,” Choo said. “I’m not trying to hit home runs. I’m trying to see a lot of pitches, get on base, have tough at-bats, show a good example for younger players. That’s my job, not hit home runs.”

Pence on hold in Frisco

Injured outfielder Hunter Pence is expected to play for Double-A Frisco on Saturday and Sunday before possibly being activated on Tuesday against the D-backs. Pence requested more time after going 0-for-4 with three strikeouts on Friday night.

“He just said his timing is off and he wants to get more at-bats,” Woodward said. “I understand that.”

Pence has been on the injured list with a strained right groin muscle since June 17. The RoughRiders have night games against Amarillo on Saturday and Sunday night in Frisco.

Rangers beat

• Shortstop Elvis Andrus had two more stolen bases on Friday night, giving him 21 for the season. He has 10 seasons of 20-plus stolen bases, the most in Rangers history. He is their all-time leader with 293 stolen bases.

• Left-handed reliever Zac Curtis, who pitched in eight games for the Rangers last year, has been released from Triple-A Nashville.

• D-backs right-hander Zack Greinke is scheduled to pitch Sunday against the Cardinals, meaning he won’t pitch in the two-game series against the Rangers on Tuesday and Wednesday. The D-backs are scheduled to pitch left-handers Alex Young and Robbie Ray.

Young is 2-0 with a 0.68 ERA over 13 1/3 innings between two starts and one relief appearance for the D-backs. He was drafted by the Rangers out of high school in 2012 but did not sign. Instead, he went on to pitch at TCU and was a second-round Draft pick by the D-backs in 2015.