The person spoke on condition of anonymity to AP on Thursday because no public comments have been authorized.

The 2019 games are set for June 29-30. These will be the first regular-season MLB games in Europe. The Red Sox will be the home team for both games.

London Mayor Sadiq Khan scheduled a news conference for Tuesday with baseball commissioner Rob Manfred but did not announce the subject matter.

"I've never been to London, so I'm looking forward to that," Yankees manager Aaron Boone said Thursday.

"But it's a long ways off. But hopefully it's something that's good for our game, can grow our game. We're obviously, hopefully, getting two good teams out there, [and that] will be a great thing for this sport.

Both teams have a European connection. The Fenway Sports Group is the parent company of the Red Sox and Liverpool in the Premier League. The Yankees have an ownership stake with the Premier League's Manchester City in the New York City FC team in MLS.

Baseball officials have long hoped for games in London and settled last year on Olympic Stadium, which is in its second season as home of West Ham of the Premier League. Because it originally was built for a 400-meter track, Olympic Stadium is wider than other large stadiums in the London area and can best accommodate the dimensions of a baseball field.

Each player on the trip will get an extra $60,000 for participating in the games, according to baseball's collective bargaining agreement.