Davide Astori
Davide Astori [Reuters]

Manchester United have been encouraged in their pursuit of signing Cagliari defender Davide Astori after the Italian club's president Massimo Cellino admitted the centre-half can leave for cheap in the ongoing transfer window.

The Italian international has been linked with a move to Old Trafford and has been monitored by United manager David Moyes, who was in attendance during Juventus' 4-1 victory over Cagliari. The former Everton boss has been closely watching his transfer targets from both clubs.

The 27-year-old has started in 18 league games for the Serie A outfit. Cellino claims that Astori could follow Radja Nainggolan, who was signed by AS Roma on loan for €3m until the end of the season and could join them on a permanent deal for €6m in the summer.

Cagliari president admitted that there were offers for Nainggolan's services from clubs across Italy and Europe for his services, but was forced to leave the club and join Roma in January. Cellino hinted that Astori could also be allowed to leave in the mid-season transfer window.

"If tomorrow I was asked about Astori or others, I would let them go. I cannot protect my boys and so I could give them all away, as was the case for Nainggolan," Cellino said, as quoted by Goal.com.

"Radja was wanted by PSG and Manchester City, but I succumbed to Roma. He did not want to leave, he had to. Zenit were willing to pay €25 million (£20m) last summer, Juventus offered €20m (£16.5m) and were prepared to let me have him until the end of the season (on loan)."

"But he could not stay here. How can he grow in a team with no ambition? He has gone to Roma. There he will grow with champions like (Francesco) Totti and (Daniele) De Rossi, a good coach and a club that already loves him," Cagliari president concluded.

United's central defending duo of Nemanja Vidic and Rio Ferdinand have less than six months left on their contract. Any move for the Premier League champions for Astori could see him being a long-term replacement for the former England international, while the Serbian is still considering his future at Old Trafford.

Should Astori join United in January, he could be made available for the Champions League tie as he has not featured in the European competitions this season.