The NFL announced today that it will allow teams to seek limited three-year sponsorships from blockchain companies, but the reversal keeps in place a ban on promotions featuring a coin or token.

"Clubs will continue to be prohibited from directly promoting cryptocurrency,” the league said in a memo obtained by CNBC.

The NFL said it decided to allow promotional relationships with blockchain companies, like Crypto.com, Coinbase, and FTX, citing the growing popularity of cryptocurrency, NFTs, and the NFL's evaluation of blockchain technology.

"We're extremely bullish on blockchain technology," Joe Ruggiero, head of consumer products for the NFL, told CNBC. “We think that it has a lot of potential to really shape innovation, shape fan engagement over the course of the coming decade."

While the news of the NFL's change of heart may surprise some, the league has tentatively looked into blockchain-related sponsorships for some time. Last year, the league lobbied the SEC on "issues related to blockchain technology."

"In this evolving regulatory environment," part of today's memo read, "it remains essential that we proceed carefully when evaluating potential commercial opportunities involving blockchain technologies, and conduct appropriate diligence on all potential partners and their business models."

But while the NFL is just beginning to explore blockchain sponsorships, athletes and other leagues have already jumped in. Last year, NBA star Kevin Durant, an early investor in Coinbase, signed a deal with the crypto exchange to appear as the brand's "face."

Other athletes have partnered with or become investors and ambassadors for blockchain companies, including NFL champion quarterback Tom Brady, tennis star Naomi Osaka, and NBA champions Steph Curry and Metta World Peace.