Derek Holland will start Friday's opener and Yu Darvish is scheduled to go on Sunday. But Saturday's starter, and rookie right-hander Nick Tepesch's turn in the rotation and when he'll next pitch, is undetermined. The Rangers could do some other juggling with the help of Monday's first off day after 20 straight games.
The Rangers will make a decision after Thursday afternoon's game against Oakland.
"It's TBD," manager Ron Washington said. "We have something in mind. But we're not ready to announce it yet. To be announced."
Martin Perez, who would be pitching on regular rest Saturday, is a likely option for the Rangers in the middle game against the Cardinals. Perez has been pitching extremely well at Triple-A Round Rock where he is 4-0 with a 1.18 ERA in his last four starts.
The Rangers could push Tepesch back to Sunday, giving him an extra day of rest. That would give Darvish extra rest and allow him to start the series opener Tuesday in always hostile Yankee Stadium against New York.
Rookie right-hander Justin Grimm would start Wednesday and Holland on Thursday. Spot starter Josh Lindblom, who pitched against Oakland on Thursday, could be the odd man out.
The Rangers are trying to get Tepesch back on track. He has allowed 17 runs on 19 hits, including three home runs, in his last 15 2/3 innings and has seen his ERA balloon to a season high 4.84.
Tepesch threw a regular bullpen in between starts Wednesday and worked on the command of his fastball, slider and curveball.
"I'm really focused on locating my pitches," Tepesch said. "I did a good job of that."
Tepesch said that it's not all about his fastball. During a six-run inning Monday against the A's, Tepesch was also hurt by leaving his slider and curveball over the plate.
"It's a combination of all of them," Tepesch said. "I made other mistakes besides with my fastball."
Cruz a hit in three-hole: Right fielder Nelson Cruz had three hits in his first start batting third in the lineup since Sept. 2010. He was back there for Thursday's game.
The Rangers will ride Cruz, who appears to be getting on another hot streak. He is batting .342 over his last 11 games and had two home runs in the Rangers' 8-7 victory over Oakland on Monday. Cruz has mostly batted fifth behind Adrian Beltre.
"I'm sorry I never thought of putting him in there before," Washington said. "I'm always thinking about him protecting Beltre. He's been a three hitter in his career. He's been a four hitter. But for some reason I got locked in on him only protecting Beltre."
Washington said he won't commit to Cruz in the No. 3 spot. But with designated hitter Lance Berkman struggling and dropping down in the lineup, Cruz could be the guy for a while.
"Let's see how it goes," Washington said.
Moreland ready to go: Mitch Moreland will be back at first base Friday in St. Louis. Moreland crushed Double-A pitching his last two games on Tuesday and Wednesday, going 6-for-9 with a home run and three doubles.
"He did what he should do against that young pitching," Washington said. "Eat it up."
Berkman gets another day: Berkman had his third game off in four days as the Rangers try to keep their 37-year-old designated hitter rested. Berkman homered from the right side of the plate Wednesday night, but struggled again hitting left-handed.
"I just want to try to keep him strong," Washington said.
Berkman has said he's having trouble straightening out his right leg, which is impacting his bat speed hitting left-handed. His last three home runs have all been right-handed. He has averaged a homer every 15.5 at-bats left-handed for his career.
Rehab pitching updates: Right-hander Alexi Ogando (right shoulder inflammation) threw long toss again Thursday. Meanwhile, righty Colby Lewis (pronator surgery rehab) threw a bullpen Thursday and will work out with Double-A Frisco while the Rangers are on their road trip to St. Louis and New York.
Left-hander Matt Harrison (back surgery) threw again from 60 feet Thursday and will up it to 75 feet next week. Right-hander Neftali Feliz (Tommy John surgery) will throw his second 25-pitch bullpen session on Friday.