In a statement, Napoli said that Nigeria forward had hurt the femoral bicep in his right thigh, an injury suffered in the first half of Wednesdayโs 4-1 hammering of Liverpool in Naples.
The 23-year-old was substituted four minutes before half-time in the Champions League win at the Stadio Maradona and replaced by recent signing Giovanni Simeone.
Osimhen is expected to be out until at least after this monthโs international break.
He will almost certainly also miss next weekโs Champions League trip to Scottish club Rangers and their clash with title rivals AC Milan the following Sunday.
