PITTSBURGH -- Chris Archer won’t be pitching for the Pirates this year.

Archer underwent surgery to relieve symptoms of neurogenic thoracic outlet syndrome (TOS) on Tuesday, the Pirates announced on Wednesday morning. This could bring about the end of Archer’s time in Pittsburgh, which began with a well-intentioned but ill-fated trade with the Rays, if the club does not pick up his $11 million option for next season.

According to the Pirates, Archer is projected to return to full competition for the 2021 season. His operation was performed by Dr. Robert Thompson at Washington University in St. Louis. The Pirates said the decision was made “after consulting with several leading vascular and orthopedic surgeons in recent weeks.”

In a conference call with reporters on Wednesday, Pirates general manager Ben Cherington and director of sports medicine Todd Tomczyk provided few specific details regarding the nature of Archer’s injury and the decision-making process that led to him undergoing surgery during this time of uncertainty. Archer, who will remain in St. Louis as he recovers, was not available to comment on his status or his future with the Pirates.

In February, Archer’s Spring Training progression was set back by neck tightness. He was scratched from a scheduled start on Feb. 24 and he did not make his Grapefruit League debut until March 6. According to Tomczyk, Archer gave “some signals” at the end of camp that his neck was bothering him again, but he remained on a monitored throwing program after players went their separate ways when Spring Training was suspended due to the coronavirus pandemic.

Cherington said Archer experienced some symptoms commonly mentioned by pitchers with TOS, but not all of them. Tomczyk noted that Archer experienced those symptoms hours and sometimes days after throwing, not during those sessions or even immediately afterward, and called Archer’s injury a “diagnosis of exclusion.”

“What is consistent with TOS is the inconsistencies, so that’s what makes it sometimes challenging to make a clear-cut diagnosis,” Tomczyk said. “But Chris is and was very diligent with marking down what he felt, when he felt it, to help himself and help us and the physicians really pin down the correct diagnosis so we could help him move forward.”

Doctors determined that his throwing shoulder and elbow were structurally sound, Tomczyk said, and experts initially ruled out the possibility that he had thoracic outlet syndrome. However, Tomczyk noted that it can take time for doctors to definitively diagnosis the syndrome; reliever Nick Burdi visited multiple doctors before having a similar surgery last year, for instance.

“What we know is that in the process of getting to the bottom of what Chris was feeling this spring, we ruled out a lot, and we were left with this diagnosis,” Cherington said. “And after a couple consultations with leading vascular surgeons, Chris felt it was time for surgery.”

Tomczyk said the 31-year-old right-hander is confident he will experience a “full return” to the mound, but it’s worth noting that many pitchers, notably including Matt Harvey, have struggled to regain their prior form after this surgery. It could take six to eight months before he is cleared to throw again, depending on how he recovers.

But will his next step come somewhere other than Pittsburgh? That seems like a strong possibility at this point. The Pirates previously exercised Archer’s $9 million option for this year, making him the team’s highest-paid player, despite the fact that he’s been occasionally injured and often ineffective since they acquired him just before the 2018 Trade Deadline for All-Star outfielder Austin Meadows, right-hander Tyler Glasnow and pitching prospect Shane Baz.

A two-time All-Star and one of the Majors’ more durable starters in Tampa Bay, Archer is 6-12 with a 4.92 ERA and a 1.40 WHIP in 172 innings over 33 starts for the Pirates since August 2018. He missed his final start of the ’18 season with what the Bucs called “continued discomfort of a left groin strain,” then two months later underwent surgery to repair a bilateral hernia. He was ready for Spring Training in '19, albeit after an abbreviated offseason training routine, then went on the injured list twice and finished the season sidelined by what the team described as right shoulder inflammation.

Archer reported to Pirate City this year with shorter hair, a simplified pitch mix and plenty of hope that this year would be different. He said he was healthy, encouraged by the changes he made in the second half of last season and excited to work with new pitching coach Oscar Marin.

This offseason, the Pirates will have to either pick up his $11 million option or buy him out for $250,000 without seeing him throw a pitch the rest of the year. Cherington wouldn’t tip his hand on Wednesday, but it’s hard to imagine Pittsburgh placing an $11 million bet on a pitcher coming off this kind of surgery.

“We won’t have games to evaluate, but there will be other information that we have at that time that we don’t have now. So we’ll just want to take all the time we have,” Cherington said. “With really any decision that we’d make in baseball operations, we want to take all the time we possibly can until we have no time remaining and then make the best decision we can at that time.”

If they’re able to play this year, the Pirates must fill Archer’s spot in the rotation while also moving forward without Jameson Taillon, who will return in 2021 after recovering from Tommy John surgery this year. They should be able to put together a starting five (or six) with Joe Musgrove, Trevor Williams, Mitch Keller, Derek Holland, Steven Brault and/or Chad Kuhl, with depth options like JT Brubaker and James Marvel also available.

Cherington said the Pirates have discussed more creative pitching plans, too. During an interview on KDKA-FM, manager Derek Shelton said there’s a “strong likelihood” that Pittsburgh will use an opener or “piggyback” pitchers, deploying multiple multi-inning arms instead of a traditional starter.

“We believe that we have a good, healthy group of pitchers who have a chance to be effective at the Major League level this year. Some of them will be in more traditional starting roles. Some may not,” Cherington said. “In some cases, when we get to play, you may see different ways to get to those 27 outs. That’s something that we’re fortunate that Shelty and the coaching staff are really open-minded and creative with. So, again, we’ll focus on continuing to prepare the group of pitchers that we have for that, and we’re all hoping to get to games as soon as we can.”