"Following a fall, the defender suffered fractures to the transverse processes of two lumbar vertebrae," Napoli said in a statement.

Napoli did not say for how long Italy international Buongiorno would be out but Italian media report a minimum of six weeks.

Buongiorno has made 15 starts for Napoli since signing from Torino in the summer, scoring one goal, and has nine international caps.

Napoli trail league leaders Atalanta by two points and travel to Genoa on Saturday.