Chelsea have been warned that a move for Borussia Dortmund ace Jadon Sancho would be extremely expensive by former Liverpool midfielder Dietmar Hamann.
The Blues are among a host of clubs being attributed with an interested in the England international, along with Premier League rivals Manchester United.
Sancho has excelled in the past 18 months to attract a wealth of interest, performing for both club and country, and Hamann has spoken about his exceptional form.
However, he has suggested that Sancho is currently the second-most valuable player in world football, behind only Paris Saint-Germain forward Kylian Mbappe.
“He has been tremendous. On Dortmund, we’ve seen in the past that they develop players and give them time.
"When he first came here, he had a rough start for the first few months but you’ve got to say, the last 12-18 months he has been one of the best players in the Bundesliga.
“I’m not surprised that there is huge interest in England to take him back to England. I’ve rarely seen a player in the last decade who beats players purely with his skill and I think he is in double figures again this season for goals and assists.
"At his young age, I’d probably make him the highest value player, maybe Kylian Mbappe is the only player valued higher, this is how good he has been.
“It will be a major act for Dortmund to keep him this summer. Obviously, we don’t know what is happening with the transfer market in these strange times but he has made a big impact.
"I just wonder what they must think at Manchester City because they must have seen that he has got something, otherwise it would not have been possible to achieve what he has done.”
