Nippert was starting at Oklahoma, but the Rangers need him as a reliever. However, they may be looking for two starters for Tuesday and Wednesday if Hurley and Padilla can't pitch. Matt Harrison may be next up from Oklahoma.
Hurley is dealing with a tight left hamstring and reported some improvement on Saturday. Hurley played long toss on Saturday and said he feels he should be ready by Tuesday, but the Rangers are still uncertain.
"It seems a lot better today but he's still doubtful for Tuesday," Connor said. "We don't want him out there unless he's 100 percent. He's got to show us he can run, sprint, cover bases. You don't want him going out there less than 100 percent."
Padilla has been bothered in his last two starts by a strained muscle in the right side of his neck. He has a bullpen session scheduled for Sunday and that could give the Rangers an indication if he'll be ready to go.
"We just don't know yet, we'll wait and see," manager Ron Washington said. "We'll wait until he throws in the bullpen tomorrow."
Harrison's next scheduled start for Oklahoma is on Tuesday, so he could shift seamlessly into Hurley's spot or be held back a day to replace Padilla. Harrison is 6-3 with a 3.43 ERA in 15 starts combined at Double-A Frisco and Oklahoma. He made six starts at Oklahoma and is 3-1 with a 3.55 ERA, including 2-0 with a 2.37 ERA in his last three starts.
If Hurley pitches on Tuesday and Harrison is needed Wednesday, then the Rangers would be going with three rookie pitchers in their first three games against the Angels. Luis Mendoza is scheduled to pitch Monday. Scott Feldman, who is not a rookie but still in his first year as a starter, is scheduled to pitch on Thursday.
"I think we'll be OK in the short-term," general manager Jon Daniels said. "We'll just see if Hurley and Padilla can make their starts. This comes with the Major League season, guys just have to pick it up and play through it. If it turns out to be something more significant, we'll deal with it. But this team has proven several times that it can bounce back."
Nippert was 6-2 with a 3.98 ERA in 12 games for Oklahoma, including 10 starts, which included a seven-inning no-hitter against Omaha in his last start. He is 4-1 with a 3.00 ERA in his last seven games.
"I've just been able to locate my curve ball and off-speed pitches better and keep my fastball down," Nippert said. "I've had good defense behind me, that never hurts either."
Nippert started the season with the Rangers, but went 1-2 with a 16.62 ERA in six games before going on the disabled list with a bruised right foot on April 22.
The Rangers made several pitching moves within their farm system. Thomas Diamond, who is still coming back from Tommy John elbow reconstruction surgery, has a bone spur in his foot and is expected to have surgery to remove it. The procedure will probably sideline him three weeks.
The Rangers promoted Neftali Feliz from Class A Clinton to replace him. Michael Main, who was the Rangers second first-round pick last year, has been moved from the Arizona Rookie Rangers to Clinton.