The Italian defender has been training at his home in Gazzetta dello Sport.
The 24-year-old arrived in Turin last month.
The move was announced after his contract expired at Stadio San Paolo on July 1.
He scored the winner in Turino’s 3-1 defeat of Juventus on Friday.
Caglia is in the final year of his current deal, but is eligible for the transfer market.
He joined the Rossoneri in 2013 and is currently second in Serie A. Caggiari has been working hard to regain fitness after his recent injury and is looking forward to the upcoming Serie A campaign.