Chelsea have already had numerous offers for John Stones turned down by Everton, and according to The Evening Standard the deal could be pushed into further doubt by the interest of Man Utd.
Everton are playing hardball with Mourinho and refuse to budge on the price tag, and with Manchester United now sniffing around, reports say Stones' value could rise further than Chelsea are willing to pay.
The 21 year old centre back, born in 1994 (how old do YOU feel?) is also a target for Man City, to whom money will be no issue. City hold the current transfer record for the league's most expensive defender, paying £31.9m for Eliaquim Mangala last summer.
Chelsea know they must buy in a long-term replacement for John Terry if they are to consolidate their position at the top of the table, and the highly rated Stones is said to be Mourinho's top pick.
What do you think Chelsea fans? Is this the man to fill Terry's boots?