The Rangers said during their game Tuesday night that Oswalt had been examined by team physician Dr. Keith Meister.
Oswalt, who Sunday made his first start since Aug. 23, left that game after two innings because of right flexor soreness near his elbow.
The team says Oswalt will be reevaluated in two or three days after not throwing during that period.
Oswalt joined the Rangers in late June. He is 4-3 with a 6.29 ERA in 13 games, nine starts and four relief appearances.