AC Milan and United States attacker Christian Pulisic won’t be part of the team that takes part in the Gold Cup, sources confirmed to ESPN on Wednesday.

The reason for Pulisic’s unavailability is that he needs a recovery period after a grueling season in Europe. If he plays in Milan’s season finale against Monza on Saturday, it will be his 50th game across all competitions for the club this season.

One source told ESPN that Pulisic had been dealing with a chronic hip flexor issue as recently as March, though it is not known if that is the reason for him sitting out the Gold Cup.

The USMNT is looking to rebound from a poor showing at the Concacaf Nations League in March in which it sustained defeats to Panama and Canada.

In addition to Pulisic, the U.S. will be without the Juventus duo of Weston McKennie and Timothy Weah, as well as Borussia Dortmund’s Gio Reyna, all of whom will be participating in the FIFA Club World Cup.

“I think to keep the players fit always, it is a challenging thing,” said manager Mauricio Pochettino on Sunday. “It’s very challenging and that is why we analyze all the circumstances. I’m going to try to be right in our decisions [about the roster].”

The CWC could also render Johnny Cardoso unavailable if his reported move to Atlético Madrid goes through.

The USMNT opens its Gold Cup group stage on June 15 against Trinidad and Tobago followed by games against Saudi Arabia on June 19 and Haiti three days later.

Before the Gold Cup, the U.S. will tune up with a pair of friendlies against European heavyweights Turkey on June 7 and Switzerland on June 10.

When it comes to the preparations for the Gold Cup, Pochettino indicated that the players involved in the upcoming friendlies would also be the ones playing in the Gold Cup.

“I think under our consideration, the percentage is going to be high, the players that are going to be involved in the first two friendly games and then in the Gold Cup,” Pochettino said. “I think it’s a logical decision because I think if you want to prepare [for] the Gold Cup, I think you need your players being fit in the competition and in training.”

Fox Sports was first to report the news of Pulisic being unavailable for the Gold Cup.