Milan travel to Arsenal for their Europa League last-16 second leg on Thursday without a recognised right-back.
“[Ignazio] Abate has a small injury to the soleus in his left calf and is being treated,” said Milan doctor Gianluca Melegati.
“For now, it’s difficult to make a prediction on his return, but his recovery time won’t be long.
“[Davide] Calabria, on the other hand, seems to be suffering from a thigh strain. He’ll remain at Milanello for precautionary treatment and we hope to have him back for Sunday’s match.”
Andrea Conti is still not ready to return, amidst reports that the Rossoneri tested versatile attacker Fabio Borini in the position.
The Diavolo trail 2-0 from the first leg at San Siro and must score at least two goals without conceding to have any chance of the quarter-finals.
Milan squad for Arsenal: A Donnarumma, Donnarumma, Storari; Bonucci, Musacchio, Rodriguez, Romagnoli, Zapata; Biglia, Bonaventura, Calhanoglu, Kessie, Locatelli, Montolivo; Borini, Cutrone, Kalinic, Andre Silva, Suso
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