Despite interest from the Red Sox, Cardinals and Rangers at various points in the offseason, the veteran right-hander might wait until midseason to join a Major League club.
"After much thought and careful consideration, Roy has decided to continue to evaluate his options," Oswalt's agent, Bob Garber, said in a statement Thursday. "He is in great health and will continue to stay in shape, while throwing regularly off the mound. Roy has every intention of pitching for a contending club at some point this season."
Oswalt, 34, could follow in the footsteps of Roger Clemens, who returned to the mound in the summers of 2006 and '07 with the Astros and Yankees, respectively.
A three-time All-Star, Oswalt has compiled a 159-93 record with a 3.21 ERA in 11 seasons with the Astros and Phillies. In 23 starts last season, he went 9-10 with a 3.69 ERA.