Liverpool and Manchester United are also in the hunt for the youngster, with boast a price tag of £120m.
Chelsea have money to burn, having been restricted in their recent spending by a transfer ban last summer.
However, any move for Sancho may significantly dent the funds available for a new left-back.
And with Leicester demanding in excess of £80m for Ben Chilwell, the Blues may be forced to turn their attentions elsewhere.
Alex Telles is believed to be next on the wishlist and could be available for even less than his £40m release clause.