BOSTON — Rays ace Alex Cobb has a partially torn ligament in his elbow that jeopardizes not only this season but potentially all of 2016 as well.Cobb is expected to try to resume pitching with the injury after at least two weeks of rest and treatment to see if PRP therapy, in which platelet-rich plasma is injected to speed healing, helps. If he cannot, he likely would have Tommy John surgery and be sidelined for most and maybe all of the 2016 season.The Tampa Bay Times was the first to report Tuesday that the setback which halted Cobb's rehab was actually a diagnosis of the tear based on a more detailed MRI exam, known as an arthrogram, during a visit to see specialist Dr. James Andrews. That was also where Cobb received the PRP injection.Rays baseball operations president Matt Silverman said only that the team was in a "wait-and-see mode" based on the results of testing and would have an announcement later in the week. He also said it was "premature" to discuss surgery as an option."We're continuing to do the evaluation to figure out what the next steps are," Silverman said. "At this point, Alex is focused on getting back on the mound and pitching this season for the Rays, but there is no timetable yet."Cobb, who was not available for comment Tuesday, has been sidelined since leaving a March 17 spring game in Clearwater with what was diagnosed as forearm tendinitis then referred to as a strain.After resting and doing no more than playing catch for several weeks, Cobb started throwing off a mound April 24 and was eyeing a late May return to the rotation."He was comfortable, he was progressing, he was adding intensity to his throwing and something didn't feel right," Silverman said.The Rays don't believe Cobb was further injured during the rehab, Silverman said. The more extensive MRI exam involves an injection of dye that can create complications, which may explain why they waited."We have followed and continue to follow normal protocol with this type of injury," Silverman said. "It was a forearm strain. The forearm is closely connected to the elbow, so there is always concern with a forearm strain."There is some track record of success for pitchers who have stayed active despite partial tears, including Yankees right-hander Masahiro Tanaka, though he was recently shut down due to wrist and forearm issues, and Hall of Famer Nolan Ryan.There would not appear to be much downside for Cobb and the Rays in waiting to see if rest and the PRP therapy helps and allows him to return sometime in June. If he has Tommy John surgery, it would seem unlikely he would return until after the 2016 season anyway.Matt Moore, who had Tommy John surgery in April 2014, is on track to rejoin the Rays sometime near the end of June.Cobb, who was making $4 million this season in his first year of arbitration eligibility, is under the Rays' control through the 2017 season."Alex is a competitor," Silverman said. "He is going to do everything he can to fight through this. We'll have a lot more clarity in the coming days and the coming weeks."In other injury news:• DH/OF John Jaso remains idled by the left wrist he bruised on opening day and has yet to resume baseball activities. "It's a slowly progressing healing process for John," Silverman said. "He continues to improve but at a pace much slower than he expected and we expected."• Infielder Nick Franklin, out since spring training with an oblique injury, went 1-for-3 in his first rehab game for Triple-A Durham.• Reliever Jake McGee, rehabbing from offseason elbow surgery, struck out one in one inning in his third rehab appearance in the Durham game. Contact Marc Topkin at email@example.com . Follow @TBTimes_Rays.