All-Star closer Jeurys Familia faces potential season-ending surgery to address an arterial clot in his right shoulder, the Mets announced on Thursday. It is the latest major injury in what has already been a bruising season for the Mets, who have been without the cornerstone of their lineup in Yoenis Cespedes, starting rotation in Noah Syndergaard and now their bullpen in Familia.

The 27-year-old will undergo further tests on Friday with Dr. Robert Thompson, the St. Louis-based vascular specialist who last July performed thoracic outlet syndrome surgery on Matt Harvey.

Familia told reporters that he was experiencing no arm issues on Wednesday shortly after blowing the save opportunity in a 6-5 loss to the Giants. He surrendered four runs (three earned) on four hits while appearing in his third consecutive game.

“My arm feels great,” said Familia, who was one of baseball’s most heavily used relievers a season ago when he pitched 77 2⁄3 innings.

Manager Terry Collins defended his use of Familia, particularly in regard to Tuesday’s victory against the Giants, when the closer was used despite the Mets holding a five-run lead.

But on Thursday, Familia was sent to the Hospital for Special Surgery in New York, where doctors diagnosed the clot.

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Any absence would further compromise a Mets bullpen that has been carrying a heavy workload, the consequence of a starting rotation that has been banged up and underperforming, and of Familia’s 15-game domestic-violence suspension to begin the season.

The Mets did not release any other details about the injury, nor did they provide an estimate of how long Familia could be out of action.

General manager Sandy Alderson is expected to address the situation on Friday, when the Mets begin a road trip in Milwaukee.

Setup man Addison Reed would likely slide into the closer’s role in case of a long absence, though the Mets could also explore making an acquisition.

In 2012, Mets righthander Dillon Gee underwent surgery in July to remove a clot in his right shoulder. He was playing catch six weeks after surgery and throwing bullpens late in September, though there was no sense in rushing a return. He began the following season in the Mets rotation.

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“This stuff can get pretty serious,” Gee said in a telephone interview on Thursday. “But if you want to play again, you have to address the cause.”

Gee said he felt no issues with his arm until he noticed numbness that progressively worsened after his last start in 2012. His right hand turned purple from a lack of blood flow and doctors found the clot near his armpit. With the Royals last season, Gee dealt with another circulation issue, this time when he underwent thoracic outlet syndrome surgery after clots were discovered in his shoulder and lungs.

In both cases, Gee was treated by Dr. Thompson.

Familia has three saves and a 3.86 ERA in 9 1⁄3 innings this season. Of the 17 games he’s been eligible, he has appeared in 11, including two stretches of three consecutive appearances.

Though his command had been inconsistent, Familia had shown no red flags of a physical issue. In fact, the velocity on his two-seam fastball averaged 96.5 mph this season, representing a slight bump from a year ago.

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Of course, a heavy workload has been nothing new for Familia, who was also tasked with multiple-innings stints. Since taking over as the Mets’ closer in 2015, he has 97 saves in 165 appearances. He led baseball and set a franchise record with 51 saves a year ago. And he led baseball in games finished in 2015 (65) and 2016 (67).