Reigning Serie A champions Napoli will be without Italian international goalkeeper Alex Meret for at least a month after he tore a hamstring muscle, the club said on Wednesday.

The 26-year-old suffered the injury in the goalless draw with Monza on Friday, with scans revealing a tear in his left hamstring, Napoli said.

Although the club did not say how long he would be out, such an injury normally requires at least five weeks of recovery.

Napoli will have to rely on second-choice 'keeper Pierluigi Gollini for the next few matches, including the Italian Super Cup tie against Fiorentina on January 18.

They must already cope without Nigerian forward Victor Osimhen -- whose goals last season played a major role in landing their first Serie A title for 33 years -- as he is heading to the Africa Cup of Nations in the Ivory Coast, which kicks off on January 13.

Napoli face an uphill battle to retain their title as they sit eighth in the Italian championship, 17 points behind leaders Inter Milan.

They will hope Meret can return in time for the home leg of their last 16 Champions League tie against Barcelona on February 21, with the second leg in Spain on March 12.