Nigeria striker Osimhen was stretchered off the pitch unconscious towards the end of Sunday’s 4-2 loss in Atalanta after hitting his head following a clash with Cristian Romero.
The 22-year-old came round as he was transported to a hospital in the northern Italian city where tests revealed head trauma, and Napoli said in a statement that he would be returning south.
“Victor Osimhen is set to return to Naples on Monday evening after staying in Bergamo overnight as a precaution… The player will be undergo further assessment on Tuesday.”
Osimhen joined Napoli for a club-record fee from Lille last summer, and returned to action last month after being sidelined for over two months with a shoulder injury and coronavirus.
Despite a promising start to the season he has scored just two goals for the club.
Napoli suffered their third defeat in five league games as Atalanta warmed-up for their Champions League match against Real Madrid.
Gennaro Gattuso’s Napoli are seventh, three points off the Champions League spot, with pressure on the coach after his team lost the first leg of their Europa League tie with Granada 2-0 last week.
