OAKLAND -- Rangers third baseman Adrian Beltre reported improvement in his strained left hamstring on Monday, but manager Jeff Banister isn't ready to put him in the lineup.
Banister is targeting Thursday for Beltre's return. Monday marked the fifth straight game Beltre has missed.
"He came to me saying he could be a player tonight," Banister said prior to the series opener with the A's. "In my opinion, we need Adrian for the long haul. I'm making that decision.
"My decision is to be patient and target Thursday. He feels good. I just feel like where we are at and how we're playing, [we should] maintain the thought process of slow-playing it."
Beltre, who tested the hamstring with some light running on Monday afternoon, said it's going to be a while before he is 100 percent, but he can manage the hamstring and still play.
"I don't need to be 100 percent," Beltre said. "I'm not going to be running like that for quite a while. But I know how to deal with it, and I can manage it for a week or two until it is 100 percent."
Beltre injured the hamstring running the bases in a game against the Astros last Wednesday. Jurickson Profar has been playing third base in his absence.
"It's on me," Beltre said. "If I play, I've got to manage it, be able to contribute and not make it worse. I just want to make sure it continues to improve. For me it's easier to be patient, because we are winning. The team is playing well."
Choo activated: The Rangers have activated outfielder Shin-Soo Choo off the disabled list and optioned outfielder Jared Hoying to Triple-A Round Rock. Choo had been sidelined since May 20 with a strained left hamstring.
Choo went 9-for-23 in seven games in the Minor Leagues on rehab assignment. He started in right field and batted leadoff on Monday.
"I'm happy to be here and happy to be a part of the team," Choo said. "Everybody is doing good here, and I really want to be a part of the team. It's all good; the rehab games were good.
"I'm not talking about the numbers. I'm seeing the ball good, the leg feels good. I made a couple of tough plays in the outfield, no problem. The baserunning feels good."
Nomar Mazara, who had been playing right field while Choo was out, will switch to left, although he was not in the lineup on Monday night with left-hander Sean Manaea on the mound for the Athletics. Ryan Rua started in left and went into the game hitting .375 against left-handers, fifth best in the American League.
Worth noting:
• Rougned Odor was back at cleanup on Monday, even though he went 0-for-5 with a career-high four strikeouts on Sunday. Banister has been using Odor fourth with Beltre sidelined and said, "I don't know if it's an experiment as much as the structure of our lineup that past few days. Our lineup is pretty fluid."
• Minor League catcher Melvin Novoa has received a 56-game suspension without pay after testing positive for Clostebol, a performance-enhancing substance. The suspension of Novoa, who is on the roster of the rookie-level Arizona League Rangers, is effective at the start of the 2016 AZL season.
• Cole Hamels is the 77th pitcher to record 2,000 career strikeouts, and he did it on Sunday against the Mariners in his 320th career game. Since 1913, only seven pitchers reached 2,000 K's in fewer games: Sam McDowell (309), Tom Seaver (305), Nolan Ryan (287), Roger Clemens (294), Randy Johnson (262), Pedro Martinez (300) and Felix Hernandez (310).