The likes of Manchester United, Chelsea and Liverpool have all been touted as potential destinations for the 20-year-old, who has continued to shine in the Bundesliga this season.
De Bruyne only had a few training sessions with an then adolescent Sancho in City in 2017 before moving to Germany, but said he could even see which special player he would become.
Speaking on Instagram live with Belgian teammates Romelu Lukaku and Axel Witsel, de Bruyne said: “He’s crazy. It’s weird, I trained with him several times and he was gone – amazing.
“Sometimes it’s like that but it’s good for him. Now if you want it you have to pay … I don’t want to know! “
Sancho had 14 goals and 15 assists in the Bundesliga this season before his suspension, and is widely regarded as one of the most wanted young players in the world.
Any team reportedly should have offered more than £ 100 million to try to sell Dortmund, but United striker Marcus Rashford admitted in a live Q&A Instagram on Wednesday that he would like to see his English teammate join him at Old Trafford.
“It would obviously be nice, Sancho is a great player, a new generation player,” said Rashford.
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“It’s really exciting to see him become the player he becomes. I hope we can all play together, that would be nice. “
“He’s playing the headline, he’s creative, imaginative, I think those are the things you have to do to be world class. “
It remains to be seen which club will take the first step in the race at Sancho, but could depend on the current coronavirus crisis, which could lead to the postponement of the transfer window.