The veteran, who is sidelined with tendinitis in his left knee, has made enough progress that he will begin a Minor League rehab assignment for Triple-A Pawtucket on Thursday.
"He'll throw an inning tomorrow night in Pawtucket and go from there," said manager Terry Francona. "He had a real good bullpen yesterday. [Pitching coach] John [Farrell] was real pleased. We'll get him out and get him going again."
Timlin, 42, is in the middle of a rough season. The right-hander is 3-3 with a 7.06 ERA in 24 outings.
Now that Timlin is healthier, the Red Sox are hoping he can use the Minor League outings to get back into form.
"I think it will be great for him," Francona said. "I think it will be great for him to pitch a little bit, yeah. Sometimes you can take advantage of some time to make something better. I agree with that."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.