In a statement, William Hill said under the agreement signed with Reno-based Eldorado last September, “William Hill gained the right to exclusively operate sports books at all properties owned or managed by Eldorado in the United States and to operate mobile sports betting in states where Eldorado obtains a license.”

The agreement covers Eldorado’s casinos where sports betting is and legal and extends “these rights” to any “subsequent acquisitions” by Eldorado. “Therefore, the rights apply to casinos currently owned or managed by Caesars if Eldorado’s acquisition of Caesars is completed,” William Hill said in the statement.

Eldorado and William Hill completed their partnership agreement in January. Under terms of the deal, Eldorado was given a 20 percent ownership stake in the sportsbook operator in exchange for a 25-year deal to operate facilities in the company’s casinos where sports betting in legal. The stake was valued at $50 million. Eldorado also received 13.4 million ordinary shares of William Hill US parent William Hill PLC, which is traded on the London Stock Exchange.

Eldorado said Monday it was buying Caesars in a $17.3 billion cash and stock transaction that will create the world’s largest gaming company with 60 resorts in 16 states under one name. The transaction is expected to close sometime in 2020.

Eldorado currently operates 26 casinos in 12 states; Caesars operates close to 40 casinos in 13 states, including nine resorts on or near the Las Vegas Strip, a market where Eldorado is currently absent.

Eldorado CEO Tom Reeg said Monday the company will look at selling some casinos in regional markets where anti-trust issues might exist and would consider selling one or two of Caesars Strip resorts.

Reeg said he liked several of the sports betting and sports partnership deals Caesars has signed but stopped short of saying what the process will be moving forward. Among the deals, Caesars has a marketing agreement with the National Football League that doesn’t include sports betting, and agreements with Turner Sports and ESPN to place television studios focused on sports wagering in Las Vegas at Caesars Palace and the Linq.

In February, Caesars Entertainment signed a deal with daily fantasy sports provider DraftKings that will include market access for online gaming products, such as mobile sports wagering. Financial terms were not disclosed, and Caesars will receive an equity stake in Boston-based DraftKings. It’s unclear how the Eldorado merger will effect the deal.

In addition to William Hill, Eldorado has sports betting agreement with the Stars Group, which includes a presence on the planned Fox Sports Network’s sports wagering application.“We’ll consider all the alternatives,” Reeg said.

Caesars operates its own sportsbooks in Nevada, New Jersey and Mississippi.