CLEVELAND — Masahiro Tanaka is out a minimum of six weeks and possibly a maximum of 18 months.
Brian Cashman announced Thursday night the Yankees ace right-hander and $175 million investment has a “small tear’’ in his ulnar collateral ligament and is out for at least six weeks.
Tommy John surgery, which takes between 12 and 18 months to come back from, isn’t planned at this time, but that could change depending on the rehab process.
Tanaka was examined Thursday by a trio of orthopedic surgeons in Seattle, Chris Ahmad (Yankees), Neal elAttrache (Dodgers) and David Altchek (Mets) who measured the tear at less than 10 percent.
“All three are in agreement with a diagnosis that this is a new injury, he has a partially torn ligament in his throwing arm,” Cashman said. “The recommendation of the treatment is a rehab protocol that would be one [platelet-rich plasma] injection [Monday] and then a throwing program after an exercise routine.
“The ligament tear in question is considered small. The Yankees have had success with pitchers who have had this. It doesn’t rule out the possibility of a Tommy John. All three doctors agree on the diagnosis and the protocol and we are going to follow their recommendation. They are not recommending surgery at this time and they are all hopeful that in roughly maybe in a six-week period we will have a pitcher back if he responds positively.’’
If not, Tanaka will be headed for Tommy John surgery. Former Yankees reliever Joba Chamberlain, now with the Tigers, told The Post Thursday night he suffered a complete tear of his UCL in 2011 so rehabbing his injury was never an option.
The Tanaka news was met with various reactions in the Yankees’ clubhouse following a tough 9-3 loss to the Indians at Progressive Field.
“It’s definitely not good,’’ closer David Robertson said. “You never want to hear that. He is the ace of a staff that has already lost [Ivan] Nova and CC [Sabathia]. We are catching some tough breaks right now. For us it’s a big blow but we will make do.’’
With Nova (Tommy John surgery) out for the season, Sabathia (knee inflammation) likely done, too, Michael Pineda attempting to come back from a terres major muscle injury in his back and now Tanaka, the Yankees have lost 80 percent of their Opening Day rotation.
“I’m certainly disappointed for our player,’’ Cashman said. “I’m disappointed for our organization. He’s an important piece and we’ve had a lot of important pieces that are missing in action.’’
Tanaka, who is 12-4, last pitched Tuesday. Over his last 13 ²/₃ innings he has allowed 20 hits and 10 runs.
Cashman said this is a new injury that was not seen on an offseason MRI exam when he was signed by the Yankees.
The general manager couldn’t put a success rate on the rehab route keeping the patient from surgery.
“Each player is different. … It’s hard to put a specific percentage on, every player is different,’’ Cashman said. “We have a tremendously gifted and tough player and we will see how he responds to that. There are no guarantees. If it is not a success we will look to a solution to it from the surgical side.”
Cashman refused to identify the hurlers who eschewed surgery, as the Mets Matt Harvey initially did last year before he opted for Tommy John surgery. Harvey said Thursday night he never had a percentage of his tear, but he saw the MRI exam and noticed significant fraying.
“I wouldn’t say, some of which are pitching elsewhere, some of which have pitched for us in the past and are now retired. Some in the minors. … depending on the circumstance and the size of the tear, ligaments can repair themselves,’’ Cashman said. “There are success stories. If this was an obvious situation that he needed surgery at the outset that’s what we would be doing.’’