NEW YORK -- When the Mets agreed to terms with infielder Carlos Correa on a 12-year, $315 million contract that was meant to be the capstone of their offseason, their hope was that they could finalize the deal by Christmas.

The reality is that the Mets may need to wait until Boxing Day or beyond, as team officials have expressed concerns about Correa’s medical records, a source confirmed to MLB.com on Saturday. The Mets and Correa’s representatives are working through the situation, the source added, but it’s unclear when a resolution might be reached.

The club has not officially confirmed the deal.

This issue will not necessarily prevent the Mets from finalizing their deal with Correa. According to a report from MLB Network insider Jon Heyman in the New York Post on Sunday, the Mets and Correa are optimistic that the deal can be worked out. Heyman writes that Correa's "actual on-field dependability and performance" could outweigh the concerns about his medical records.

On Monday, the New York Post’s Mike Puma wrote there’s a “55 percent” chance the two sides can find common ground, along with writing that a possible compromise is language in the contract that would protect the Mets financially if Correa was sidelined due to a pre-existing medical condition.

But it is a complicated situation. Before the Mets came to terms with Correa, the Giants walked away from a 13-year, $350 million agreement with him because of medical concerns. That prompted Correa’s agent, Scott Boras, to reengage other teams, including the Mets, who negotiated a reduced deal for the infielder in about 12 hours.

Later that week, Boras said he did not know what issue the Giants had flagged, but that it must have been something in Correa’s past.

“There is no medical issue with Carlos,” Boras said on Thursday. “There is none. And so it had to be something that they felt was historical.”

The Athletic, which first reported that Mets officials were concerned with Correa’s medicals, noted that the issue is regarding Correa’s surgically repaired lower right leg. Correa underwent arthroscopic surgery to repair a fractured right fibula that he sustained during a Minor League game in 2014, but that issue hasn’t caused him to spend any time on the Major League injured list. Per Heyman, Boras said Correa has never received any treatment related to the injury since his recovery from it.

Heyman reported Sunday that the Mets and Correa's camp have been discussing how much importance to put on an MRI of Correa's lower right leg vs. the current functionality of his ankle joint and Correa's recent history of durability (he's played 342 of 384 possible games over the last three seasons). Per the report, the Mets seem to be in more substantive talks with Correa now than the Giants were with him after their medical concerns arose.

Correa’s medical history also includes back and ankle injuries, which have likewise not stopped him from producing a career .279/.357/.479 slash line over eight seasons with the Astros. Over the past three seasons, Correa played in 89 percent of his teams' games.

“There’s been a lot of discussion about backs and ankles,” Boras said, noting that three teams have offered Correa a contract of 10-plus years this offseason. “There’s nothing about him that is currently any form of medical issue. All the conjecture and evaluation has been about physicians using their crystal balls for years to come.”

The $315 million agreement for Correa would be the largest of 10 free-agent contracts the Mets have negotiated this winter. All told, owner Steve Cohen has committed $807.1 million to free agents, including Brandon Nimmo, Justin Verlander, Kodai Senga and others.