Malick Thiaw will sit out AC Milan's match with Juventus and the Champions League game against Girona after the Serie A club said on Wednesday that he has a hamstring injury.
In a short statement, Milan said Thiaw had hurt his left hamstring, an injury that forced the Germany defender to be substituted in the second half of Tuesday's 2-1 win at Como.
"He will be assessed in seven to 10 days," added Milan.
The 23-year-old will sit out Saturday's trip to fierce rivals Juve, four days before Milan continue their bid for direct qualification for the last 16 of the Champions League against Spanish club Girona at the San Siro.
Milan added that attacking stars Christian Pulisic and Alvaro Morata, who were replaced at half time against Como, had not picked up similar muscle injuries as previously feared.
Morata is however suspended for the match at Juve after picking up his fifth league booking of the season at Como.
Sergio Conceicao's team are seventh in Serie A, five points behind fourth-placed Lazio but with a game in hand.
Milan are one point from the Champions League's top eight with two matches remaining in their league phase campaign, against Girona and then at Dinamo Zagreb the following week.