Christian Pulisic is bracing to be out for nearly a month after suffering a hamstring injury while on international duty with the United States.

Pulisic has been Milan's best player by far this season, with six goals and two assists.

Pulisic entered the international break with a right ankle injury and played a limited number of minutes in the United States' 1-1 tie against Ecuador. Pulisic then started their match against Australia before suffering his hamstring injury and leaving after 26 minutes. 

"I think it's a thing that is a massive risk. I don't want to say that Christian or if it's something because, but I think it was really tough for the player," Pochettino said. "We know to prepare the game and then to play. We got really sad about this [Pulisic] situation because I think it is difficult.

"I think the [temperature] difference [between Austin and Colorado] and that can affect your body and everything. That is difficult. But yes, that is a thing that we need to fix for the future when we come from Europe because [the altitude] can affect [things]."