Manager Trey Hillman said both pitchers would get medical evaluations on Friday and their future slots in the rotation would hinge on that. Bannister's next scheduled start is Tuesday night against the Tigers.
Robinson Tejeda came out of the bullpen to start in Meche's spot on Friday night. Bruce Chen, a left-hander who has started eight games this season, is also available in the 'pen. Triple-A Omaha's season ends on Monday, so pitchers from that club could be called up.
"We've got contingency plans in case we have to," Hillman said before Friday night's game. "We've got Bruce that we can lengthen back out as well, but it really depends how deep we get in the bullpen tonight. We'll see what Robby can give us and hopefully we don't trash the bullpen."
Meche had been bothered by back problems earlier and was slow coming around since being activated from the disabled list. In his four starts since returning, Meche has a 2-1 record with one no-decision and an ERA of 8.14. Meche lost his last game at Seattle, surrendering seven runs in four innings.
Against the A's, Bannister gave up three runs in the first inning and, after retiring the first batter in the second, it was obvious something was wrong. Later, he said his arm hasn't been completely sound since his last win on Aug. 2 at Tampa Bay. In his past six starts, he's 0-5 with a 9.30 ERA.
Jose Guillen, who returned to the lineup on Wednesday only to leave after two at-bats as the designated hitter, did not start against the Angels. Out for nearly five weeks with a right knee sprain, he left the game at Oakland with a sore right hamstring.
"I'm good to play," Guillen said. "The knee brace was just too tight. Nothing's wrong with the knee, it's fine."
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.