Griffin is the second A's starter -- Jarrod Parker underwent his second Tommy John surgery in late March -- and one of over a dozen pitchers around the Majors to undergo the operation in the last month.
The club's head trainer, Nick Paparesta, said Griffin's procedure went extremely well, noting that no cartilage needed repair and the ulnar nerve did not need to be moved. Dr. Thomas Mehlhoff, who also performed A's reliever Fernando Rodriguez's Tommy John surgery with successful results, was able to use the Palmaris tendon from Griffin's right wrist as a graft.
"The joint looked great," said Paparesta. "Dr. Mehlhoff was very excited, encouraged about the graft, and he feels pretty good about how it came out."
All of these things will help Griffin's recovery, as will the fact he's still just 26-years old. Moreover, the mental challenge that comes with such a lengthy rehab will be aided by Parker's company.
Griffin won 21 games for the A's the last two years, posting a combined 3.60 ERA.
"I think it's going to be great for A.J., because Jarrod's been through it," said Paparesta. "So when A.J. has all those questions, Jarrod will be there to help with a lot of them."
Paparesta's staff hopes to use the time to help Griffin improve his overall physical condition.
"We do want to take a holistic approach," he said. "We want to find A.J.'s weaknesses, if his core strength is where it needs to be, if his rotator cuff strength is where it needs to be. Does to he need to work on his lower half? Does he need to work on his upper half, and does he need more flexibility? And then we put all of that into the rehab program. It's not just come in and do two hours of therapy on the elbow and go home. It's about putting together the best package we can for him."
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.