Real Madrid feel Raphael Varane will 'ultimately decide to extend' his stay at the club, according to reports. Manchester United have been strongly linked with a move for Varane this summer. The France international is out of contract in the summer of 2022.
Castles said: "Madrid I can tell you have in fact made him an improved offer to sign a new long-term contract at the club, which would guarantee him €7million a year after tax.
"So it's a very substantial deal for the player. Varane and his father, who is his main advisor, have said 'we don't want to make a decision on that during the season, we'll come back to you at a later stage'.
"My guidance is Varane and his father are playing a very careful game here.
"They know that with just one year of contract left if they were to stay at Real Madrid for that final year, they would be expected to be able to secure a higher salary than €7m as free agents in a year's time.
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy
Manchester United transfer news: Raphael Varane is linked with a move to Old Trafford (Image: EXPRESS)
"They know that Madrid want to keep them and have already made a substantial offer, and they know that other clubs, including Manchester United, are interested in signing the player."
United boss Ole Gunnar Solskjaer wants to sign a long-term partner for club captain Harry Maguire.
But Castles says there is belief at Real that Varane will end up signing a new deal and enter his 11th season at the club next term.
"Within Madrid there is a feeling that Varane will ultimately decide to extend," he added.
"So it's certainly not clear cut that he will definitely leave the club and definitely accept an offer to go to Manchester United, or one of those other suitors, rather than just use it as a way to organise the best financial terms of Madrid this summer, or wait another year and look for even better personal terms in a year's time."