The 26-year-old Italy international has been heavily linked with a move to the Premier League, with Liverpool and Southampton both monitoring the player during the January transfer window.
Now, new Old Trafford boss David Moyes has entered the race to sign Astori, as he bids to strengthen Manchester United's defence ahead of the start of the 2013/14 campaign.
The Premier League champions have been credited with an interest in a number of different central defensive options, with Benfica's Ezequiel Garay and Inter Milan's Andrea Ranocchia also both believed to be on United's radar.
However, Astori has emerged as the latest centre-back to catch the eye of Moyes, after an impressive 2012/13 campaign for Cagliari, where he made 32 appearances in Serie 'A'.
With a valuation of £10million, he would also represent the cheapest option of the three aforementioned defenders, should Manchester United press ahead with a deal for the Azzurri star.
AC Milan and Napoli could rival Manchester United for Astori's signature, though, as they too line up bids for the commanding Serie 'A' stopper.