The Rangers expect Darvish to be ready for spring training, general manager Jon Daniels said Thursday morning.
"We're hopeful it will resolve the issue," Daniels said. "We expect him to be 100 percent."
The issue caused Darvish to lose strength in his right right leg, Daniels said. Darvish could be seen several times toward the end of the season tapping the area with his right hand between pitches.
"He wasn't as powerful as he wanted to be after being out there for an extended period of time," Daniels said.
Despite the issue, Darvish led the majors with 277 strikeouts. He was 13-9 with a 2.83 ERA.
Daniels said the problem started in August but that Darvish decided not to have the injection toward the end of the season because he didn't want to miss a start. The GM also said Darvish's injury is not similar to the one that caused Opening Day starter Matt Harrison to miss most of the season.
Harrison's MRI showed issues with a disc in his lower back, and he ultimately needed two surgeries. Darvish's MRI was as normal as it can get, Daniels said.
Darvish was scheduled to leave for Japan on Thursday or Friday and return to Arlington in November.