Gomez picked up the issue in September's 1-1 draw with Cagliari and has suffered setbacks in his return to fitness.
Having only made three Serie A appearances since joining from German champions Bayern Munich, the 28-year-old will return to training with his team-mates this week after completing his rehabilitation.
However, ahead of Tuesday's Coppa Italia semi-final first leg, Vincenzo Montella has been hit by injuries to Alberto Aquilani and Massimo Ambrosini.
Aquilani suffered a grade one hamstring strain in Saturday's defeat to Cagliari while Ambrosini will see a specialist due to Achilles tendinitis.
Meanwhile, Ante Rebic and Nenad Tomovic will continue to recover from their respective injuries in the week.
"Ante Rebic is suffering from metatarsalgia in his big toe and will have physiotherapy over the coming week," a club statement read.
"Medical tests carried out on Nenad Tomovic revealed that he has made progress in recovering from his knee sprain. He will therefore continue his rehabilitation by following a personalised programme on the pitch for the next 10 days."
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