The full-back has been a regular for Roberto Mancini's side this season as they have climbed to the top of Serie A – where they sit level with Fiorentina on 27 points from 12 games.
Santon has started nine of those matches, but looks set for a period of rehabilitation after a scan on Tuesday revealed a slight problem with his heel.
"Davide #Santon undergoes ultrasound scan that reveals a small haematoma in his right Achilles tendon," the club announced on Twitter. "More tests to come in following days."Inter welcome Frosinone to San Siro on Saturday looking to record a fourth successive league win, while Fiorentina host Empoli.