The anticipated rematch of heavyweights Cain Velasquez and Fabricio Werdum at UFC 207 is off after the Nevada State Athletic Commission sidelined Velasquez due to medical issues.

Via the NSAC:

"Based on medical records, interviews and the best judgment of Chairman Anthony Marnell, attorney general J. Brin Gibson, the executive director's office and our physicians, in an effort to protect the health and safety of the athletes, it's been determined Cain Velasquez is unfit to fight. "The financial incentive for fighters to compete is strongly compelling, and it is the responsibility and obligation of this commission to intervene when excessive risks are evident. It's obvious Mr. Velasquez is physically compromised, and competing would place him in significant physical risk."

No details were provided as to Velasquez's specific medical issue, and UFC has not commented about the ruling at this time. ESPN first reported the fighter being pulled from the event. Velasquez has previously complained about back pain, and he has only fought twice since 2014.

After hearing about the NSAC's decision, Velasquez sent a series of tweets expressing his confusion to the situation.

Haven't heard I'm out of #ufc207, as far as I know it's still on... @FabricioWerdum — Cain Velasquez (@cainmma) December 24, 2016

Was just cleared by Dr 30 mins ago and then he conferenced the Nevada Athletic Commision and spoke to them and recleared me with them. — Cain Velasquez (@cainmma) December 24, 2016

Not sure what is going on... #ufc207 — Cain Velasquez (@cainmma) December 24, 2016

Velasquez-Werdum was the second major bout set for UFC 207 on Dec. 30 in Las Vegas behind Ronda Rousey's return match against Amanda Nunes. It was a rematch of the heavyweights' UFC 188 bout where Werdum upset Velasquez to take the title.

A rematch was originally scheduled for February but scrapped due to an injury to Velasquez. In his first title defense, Werdum lost the belt to current champion Stipe Miocic at UFC 198 in Brazil.

Both fighters won their most recent bouts, with each fighter defeating Travis Browne. Velasquez did so in impressive knockout fashion at UFC 200, while Werdum beat Browne by unanimous decision at UFC 203.

The winner of Velazquez-Werdum was expected to be the No. 1 contender for Miocic's title. Now UFC Must decide whether to find Werdum a new opponent or scrap the bout entirely with one week until UFC 207.