Nicasio was reassigned to the Rangers' alternate training site Sunday, Levi Weaver of The Athletic reports.
Nicasio worked through back tightness during spring training but appeared to be healthy this summer. He was able to pitch in intrasquad competition, but he'll play at the team's alternate training site to start the regular season. Even if he reaches the majors at some point this season, the 33-year-old is unlikely to play a significant role.