Polymarket US says it followed guidance from a federal regulator and withdrew plans to offer trading on Patrick Mahomes’ return to the field, a type of market the NFL says should be prohibited.

On Tuesday, Polymarket self-certified a market on “Will Patrick Mahomes participate in the Kansas City Chiefs’ Week 1 regular-season game?” but withdrew the filing the following day.

A Polymarket source told ESPN on Friday that the Commodity Futures Trading Commission (CFTC) asked Polymarket and other prediction market operators to remove contracts such as Mahomes to play in Week 1. The company withdrew the filing to be in full compliance with the CFTC, the source said, adding that Polymarket continues to engage with the CFTC regarding its offerings.

The CFTC spoke with at least one other prominent prediction market operator about not offering trades on NFL player availability, according to a source familiar with the discussions. The CFTC did not immediately respond to ESPN’s request for comment.

As of Friday, leading prediction market Kalshi is offering trading on Mahomes being the Chiefs’ starter in the season opener against the Denver Broncos, in addition to other markets regarding when injured players will return. Kalshi did not respond to questions about any directions from the CFTC regarding the markets.

The NFL, in written correspondence with the CFTC, has said it objects to any markets that could be tied to injuries or officiating, as well as any offering that could be known in advance or is easily manipulable by one person.

The NFL told ESPN that it considers the proposed Mahomes market to be injury-related. Mahomes is coming off a season-ending left knee injury last year.

Jeff Miller, executive vice president of public affairs for the NFL, told ESPN that he hopes the CFTC would prohibit such markets and ultimately create a process where the league would be asked if certain markets are viable before they are posted. Miller added that, without a formal relationship, all the NFL can do is ask.

“We hope to get to the place where we have a very efficient system someday if they’re legalized in that same way that we can protect the integrity of the competition perfectly,” Miller said Wednesday at the NFL owners meeting in Atlanta.

An NFL executive said Wednesday that the league is not currently considering a commercial relationship with the prediction market industry. This week, the league announced new partnerships with three sportsbooks, DraftKings, FanDuel and Fanatics.

Prediction markets are embroiled in legal battles with multiple states over whether their offerings constitute gambling or financial swaps. On Friday, a federal appeals court in San Francisco ruled in favor of Nevada and its state gaming control board, denying Kalshi’s request to resume offering trading on sports or politics unless the company acquires a gambling license.