La Gazzetta dello Sport are now reporting that Pulisic suffered a hamstring injury that is likely to rule him out of the clash with winless Fiorentina.
“He felt something in his hamstring,” USA boss Mauricio Pochettino said after the game.
“Tomorrow he will fly to Italy, tonight we will assess, and we cannot say anything at the moment.”
The 27-year-old had met up with the USAMNT already nursing an ankle knock, but was deemed fit enough to make an appearance from the bench against Ecuador at the weekend and start last night's friendly in Colorado.

However, his game ended on the half-hour mark, and he had to sit and watch as his teammates came from behind to defeat the Aussies, thanks to two goals from Coventry's Hadji Wright.
The American skipper has been Serie A's standout player this campaign, scoring four times in the league and laying on two assists so far for Max Allegri's side.
If he's unable to play, it could mean a first league start of the season for either summer recruit Christopher Nkunku or Rafael Leao, if he's fit enough to start the game following his comeback from injury.
After Fiorentina, Milan's next game is a trip to Pisa on Friday, 24 October, but it's unclear how severe Pulisic's injury is and whether he'd also be a doubt for that fixture. Getty
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