Higuain had to be helped off the field in the Partenopei's stalemate with Inter Milan at San Siro on Saturday following a 50-50 challenge with Marco Andreolli.
With the Italian outfit poised to contest the Coppa Italia final with Fiorentina on Friday, Benitez has confirmed that the club now face an anxious wait to determine how long the prolific hitman will be sidelined for.
He told Sky Sports Italia: "Higuain has a trauma to the ankle, a bruise and we'll have to see over the next few days. We still don't know what the situation is."
The former Real Madrid marksman has struck 25 goals for Napoli in all competitions this season.