Ademola Lookman will miss Atalanta's Champions League clash at Barcelona, the Serie A club said on Tuesday, after the Nigerian star suffered a knee injury in training.
In a short statement, Atalanta said the 27-year-old forward had hurt the lateral joint in his right knee and would not travel to Spain where on Wednesday the Italians are aiming to secure direct qualification for the last 16 of the Champions League.
Atalanta did not say how long Lookman would be out but Italian media report he could be sidelined for up to a month.
Lookman will be a huge loss for Atalanta as he has scored 14 goals and set up six more this season.
He also scored a hat-trick in last season's Europa League final triumph over German champions Bayer Leverkusen.
Atalanta have punched well above their weight both in Italy and abroad in recent seasons, with Gian Piero Gasperini's side still hanging on in the Serie A title race and riding high in Europe's elite club competition.
The Bergamo-based outfit sit seventh in the 36-club league phase of the Champions League, but with a host of clubs within a point of them anything but a win at already-qualified Barca will likely mean a play-off spot.