Boston-based DraftKings and another popular betting site – Bet365 – are misusing images of hundreds of professional baseball players for marketing campaigns, according to the lawsuit filed Monday in federal court in Philadelphia, home to the Philadelphia Phillies, who currently have more wins this season than any other MLB team.

“Defendants’ use of player images on their sports betting platforms is not only for informational purposes, but also for promotional purposes,” the union’s lawyers explained in the lawsuit. “Users could bet on the Phillies beating the Marlins or on Bryce Harper hitting more than two home runs in a given game without seeing Harper’s valuable image. In fact, both DraftKings and Bet365 offer the same types of bets in other sports without using player images.”

Representatives from DraftKings and Bet365 were not immediately available for comment.

The lawsuit comes as DraftKings expands its offerings. Last month, the company acquired website Simplebet Inc., which specializes in betting during live sporting events. Simplebet was founded in 2018 and provides other bookmakers with pricing information on such bets for MLB, National Football League and National Basketball Association games.

DraftKings, a U.S. pioneer in online fantasy sports gaming, is also among more than 130 companies that have pre-registered their interest in a license to operate in Brazil, according to the Brazilian Ministry of Finance. The list of license applicants also includes MGM Resorts International and Hard Rock International, the casino operator of the Seminole Tribe in Florida.

DraftKings’ revenue has increased as the company has been able to attract more loyal betting customers, even as it has faced increasing competition from online rivals and traditional casinos, forcing the company to spend millions on advertising and gambling incentives.

In MLB’s lawsuit, the union’s for-profit unit is seeking compensatory and punitive damages and wants a judge to order the betting sites to stop using the players’ images. It is also demanding “disgorgement of all profits associated with the use of images and likenesses of MLB players on their sports betting platforms and the use of MLB names, images and likenesses in advertising and promotions for their” platforms.

The case is MLB Players v. DraftKings, 24-cv-04884, U.S. District Court for the Eastern District of Pennsylvania (Philadelphia).

(Updated with details from the lawsuit.)