Hanrahan played catch at 75 feet on Tuesday and graduated to 90 feet Wednesday. In due time, he will probably go on a short Minor League rehab assignment before being activated. He is eligible to pitch for the Red Sox again on April 30.
Perhaps a tune-up in the Minors will help Hanrahan snap out of the funk he was in early in the season, posting an 11.57 ERA in six outings.
Though Hanrahan isn't an excuse maker, he doesn't dispute that the hamstring injury could have impacted some of his pitches, particularly his breaking ball.
"It was there a lot more on my breaking ball," Hanrahan said. "I'd throw a breaking ball and kind of aggravate it a little bit. It's a funny thing, because the arm strength and velocity are still there. It kind of effects your mechanics and being able to locate the ball. We're all strong enough that we can create velocity. Velocity without location is not going to help anybody.
"It was my decision to keep going out there. If I went out there, I felt like I could get the job done. I'm not looking for any sympathy on why things happened. It's part of our competitive nature to go out there."
But with a strong foundation in his legs, Hanrahan looks forward to showing people why the Red Sox acquired him in the first place.
"Yeah, exactly," Hanrahan said. "It's tough for a pitcher to go out there without their legs. It's something I'm looking forward to, just getting back out there. I love the game of baseball, but it gets kind of boring sitting in the dugout watching and knowing you can't do anything."
Will Hanrahan regain the closer's role as soon as he returns?
"I don't think we're sitting here today ready to make that claim," manager John Farrell said. "We've got to get through some things first -- particularly how he responds with the hamstring. He's going to need a couple of rehab appearances just to get himself going again. This is a bigger-bodied guy that is a power pitcher, and we want to be sure that he feels comfortable physically before we bring him back to us, and we'll work through that at that time."
Andrew Bailey, who has 81 saves, will hold down closing duties in Hanrahan's absence.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.