"If he throws a no-hitter, he'll go into the record books," manager Ron Washington said. "I hope he throws a no-hitter, so he can go into the record books. But I'm not putting my expectations that high."
Koronka is 3-3 with a 5.40 ERA in eight starts at Oklahoma. He had a run of four straight quality starts in which he was 3-0 with a 2.60 ERA before allowing six earned runs over four innings in a loss to Tucson in his last start.
"I know he's pitched some good games but I don't know what happened in his last start," pitching coach Mark Connor said. "I haven't talked to anybody but I do know that his sinker has improved, his changeup has improved and his delivery has improved."
Koronka was in the Rangers' rotation for much of last season and was third on the team with 23 starts, going 7-7 with a 5.69 ERA. He relied mainly on a straight fastball and the Rangers have had him use his sinker much more this year.
"He didn't have enough fastball to be a power pitcher," Connor said. "We wanted him to incorporate his sinker and be more of the traditional finesse pitcher but with the ability to throw the occasional fastball inside."
The Rangers considered right-hander Willie Eyre for the start, but that changed when he was needed in relief in the 10-inning game against the Tampa Bay Devil Rays on Thursday.
"We didn't want to take Willie out of the bullpen," Connor said. "He's the most durable piece we have down there."
Sosa in right field:
Sammy Sosa returned to right field on Friday, his first start out there since April 29 in Toronto. With the designated hitter not being used in the National League park, Sosa will have to play right field to be in the starting lineup.
Washington said Sosa will start there Friday and Saturday. He'll wait and see about Sunday, which is a day game.
"I hope he does," Washington said. "It all depends if he looks a little sluggish. Sammy does need his time off now and then."
Sosa has started 37 of the Rangers' first 42 games, with 29 of those starts coming as the designated hitter. This was his eighth start in the field.
"As much as I like the DH spot, this is Interleague Play," Sosa said. "I'm not going to be Torii Hunter but I'll do the best I can."
Sosa went into Friday's game hitting .310 as a designated hitter while going just 2-for-25 when playing the field. He admitted he is more comfortable as the DH.
"In this stage of my career, I can concentrate more in every at-bat and what I have to do in the next at-bat," Sosa said. "I'm doing very good things in the DH spot. I feel good that I'm helping the ballclub there. I know I can play the field but I think my at-bats will be more productive as the DH."
Connor high on Loe:
Connor has been a big supporter of Kameron Loe, and that hasn't changed even though the right-hander has struggled of late. Loe allowed six runs in 5 1/3 innings on Thursday against the Devil Rays.
Loe is now 0-3 with a 7.62 ERA in his last five starts and 8-11 with a 5.15 ERA in 30 career Major League starts.
"I have just as much confidence in Kameron going out there and starting a game as anybody," Connor said. "Kameron is in the middle of learning on the job and is doing a better job than his numbers say. The more Kam learns to change speed with his sinker, the more effective he will be.
"I like the fact that he challenges hitters, almost to a fault. I'd rather see that in a young pitcher rather than see him back away. It's just a matter of experience, the same with Brandon McCarthy and Robinson Tejeda. They all haven't had a full year of starting. This is a tough league, and they've got to learn quickly."
Hairston on hold:
Jerry Hairston remains sidelined with a pinched nerve in his right shoulder and is not going to be available for the three games in Houston. But the Rangers are still hoping he'll be ready by Monday, when they open up a three-game series with the Minnesota Twins in Arlington, and they are holding off putting him on the disabled list. He had a cortisone shot on Thursday that usually takes two to three days to have full impact.
Triple-A Oklahoma pitcher Josh Rupe, who has a history of elbow trouble, had to leave Thursday's game with some soreness there. Levine said the Rangers are having him undergo further evaluation to get a better idea of the problem.
He said it: "When you start slumping, everybody has to figure out why. But it's not because I'm trying to hit home runs. That's not my role on this team. It's just something you go through. Nobody wants to go through it but this game is tough." -- second baseman Ian Kinsler
Thursday's Minor stars:
Top performances from the Rangers' Minor League teams on Thursday.
Class A Clinton pitcher Omar Poveda pitched 6 2/3 scoreless innings in a 1-0 victory over Dayton. He allowed five hits, walked two and struck out nine to raise his record to 4-0 with a 2.17 ERA.
Catcher Salomon Manriquez went 3-for-4 with the game-winning double in the top of the ninth inning as Double-A Frisco defeated San Antonio, 6-5. The Roughriders trailed, 5-4, going into the ninth before rallying for the victory.
Class A Bakersfield third baseman Chris Davis went 3-for-5 with two home runs in an 8-7 loss to Lancaster.
Koronka will face Astros left-hander Wandy Rodriguez at 6:05 p.m. CT on Saturday in Game 2 of the three-game Lone Star series at Minute Maid Park.