Diego Forlan is expected to be out for about a month after the Inter striker's injury was confirmed to be more serious than first thought.
The forward picked up a muscle problem in his left leg on international duty this week which was believed to be a minor strain.
However, tests today have revealed the full extent of the problem and reports are suggesting that he will be sidelined for four weeks rather than the two initially hoped.
The Nerazzurri will also be without Philippe Coutinho after he suffered a similar injury to the Uruguayan's in training on Thursday.
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