Italian media reported Immobile, who scored in Lazio's 3-0 win at Spezia on Friday, was involved in an accident after the Italy international's car collided with a tram in Rome.
"Earlier today, following a car accident, footballer Ciro Immobile suffered a spinal distortion injury and a compound fracture of the right XI rib," Lazio said in a statement.
"The condition is currently good. The footballer remains under observation in the emergency medicine department... of the Agostino Gemelli IRCCS University Polyclinic in Rome."
Sky Sport Italy said Immobile was travelling with his two daughters in the car, with the forward telling police that the tram allegedly ran a red light.
Seven others, including tram passengers, were also taken to hospital for checks.
Immobile has scored 10 Serie A goals this season to guide Lazio to second in the standings behind leaders Napoli.
