The injury could sideline the star winger for several weeks and jeopardize his availability for key Serie A matches.
According to La Repubblica, Milan view the decision by US coach Mauricio Pochettino to start Pulisic in Tuesday's 2-1 victory as an unnecessary risk, especially given the forward's pre-existing ankle discomfort. The 27-year-old was forced off after just 30 minutes, appearing to suffer a fresh muscle strain.
Pulisic had been nursing an ankle issue ahead of the international break, which Milan staff had been managing carefully. The problem kept him out of the starting lineup for the USA's 1-1 draw against Ecuador the previous Friday, and he participated in light training sessions leading up to the Australia clash.
Club officials believe Pochettino should have prioritized rest for their talismanic attacker in a non-competitive game, particularly considering his heavy recent schedule and the ongoing minor knock that required monitoring. Sources close to the Rossoneri, cited in Italian outlets, have labeled the choice as puzzling.
Pulisic was scheduled to return to Milan on Thursday but faced a flight delay, postponing his initial medical assessments originally set for that day; further evaluations are now expected as early as Friday to determine the full severity of the hamstring problem.
Preliminary reports indicate a potential absence of up to a month, which would see him miss the crucial Serie A home clash against Fiorentina on October 19, as well as the trip to Atalanta on October 28, and possibly the Rossoneri's next Champions League group stage fixture in early November.
In Pulisic's absence, Milan will turn to new signings Christopher Nkunku and Santiago Giménez to bolster the attack as they aim to hold their strong position in the upper echelons of Serie A.
The American has been exceptional in the 2025-26 campaign so far, topping the Serie A scoring charts and serving as a cornerstone in Massimiliano Allegri's system. His untimely injury represents a significant challenge for the Diavolo, who feel greater caution from the US setup might have prevented this avoidable blow.
Atalanta coach Raffaele Palladino has said Tuesday's Champions League last‑16 tie against Bayern Munich promises to be a "magical night" and insists his team will fight hard despite a difficult injury list.
Vincent Kompany has remained cautious over Harry Kane's fitness ahead of Bayern Munich's crucial UEFA Champions League Round of 16 clash against Atalanta on Tuesday night, insisting a final decision will be made on matchday morning.
Massimiliano Allegri has insisted the Serie A title race is still out of AC Milan's hands after his side secured a crucial 1-0 victory over fierce rivals Inter Milan at the San Siro on Sunday.
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