OAKLAND, Calif. — Elvis Andrus could miss the final two games of the Texas Rangers’ biggest series to date, though he said on Monday that the stiffness in his lower back had improved.Andrus said that he spent most of the three-plus hours of flying time Sunday night laying down, and he received more treatment shortly after arriving to O.co Coliseum. He’s trying to be patient with something that has bothered him much of the season.“It feels better, but I still have a lot of stiffness in there,” said Andrus, who left in the first inning Saturday. “It’s hard for me. I really want to play, but I’d rather see someone in there healthy.”Jurickson Profar was the starting shortstop and No. 2 hitter for a second straight game in the opener against Oakland. Though his throwing error Sunday and missed chance at the plate were key plays in a 4-2 loss to Minnesota, manager Ron Washington is in no hurry to rush Andrus back to the lineup.“In a perfect world, he might have just missed yesterday and been ready to go,” Washington said. “We can’t afford him to go down again. So if it just means a couple extra days, it’ll just be a couple extra days.”Berkman returnsLance Berkman returned to the Rangers’ lineup for the first time since July 6 as their designated hitter, but he won’t be returning to the everyday role he had earlier in the season.Berkman hadn’t faced live pitching since Aug. 14, but said that running on his left hip and right knee wasn’t his greatest concern. He was the No. 8 hitter, his first start there since 2010, and wasn’t sure how he would fare the rest of the way.“We’ll see. It’s hard to know,” Berkman said. “Ready or not, here we go. The main thing is just to go out there, compete, and do the best I can. I don’t know how I’m going to be at first, but I think if I get enough opportunities, I’ll be able to be sufficient in that role if they need me.”Ron Washington was planning to use Berkman again Tuesday if he could make it through Monday without any issues. But the Rangers don’t believe his body will allow him to play regularly.“He’ll let us know what we can expect,” Washington said. “I’m not going to place any expectations on him. I’ll just watch and judge and listen to him.”Here’s the pitchLeft-hander Travis Blackley is tentatively scheduled to make his next start Saturday against the Angels, but the Rangers might use an off day Thursday to push him back a few days.Bumping Blackley would allow the Rangers to throw right-hander Matt Garza and lefties Derek Holland and Martin Perez this weekend. Blackley, or the fifth spot in the rotation, would be needed Sept. 10 at home against Pittsburgh.The Rangers also could turn to Nick Tepesch or Michael Kirkman.“We’ve got three different options, so we’ll look at them all,” Ron Washington said. Alexi Ogando, who threw a bullpen session Monday and is scheduled for live batting practice this weekend, likely wouldn’t be an option. He said his shoulder, which was bothered by nerve inflammation, feels “very good.”Briefly• The Rangers recalled right-hander Ross Wolf and outfielders Engel Beltre and Joey Butler from Triple A Round Rock as September call-ups. Wolf, who had been with the Rangers since May, was sent down Friday knowing that he’d return quickly.• Adrian Beltre was named the Rangers’ Player of the Month for August. The third baseman batted .381 with five homers, 21 RBIs, 20 runs and a .479 on-base percentage in 27 games.