Sancho, then 17, left the Premier League in search of first-team football two years ago and drew plenty of criticism in doing so.
He has since earned his place in title-chasing Dortmund’s first team, established himself as one of the world’s premier attacking talents, and now appears to be battling Marcus Rashford for a starting spot for England.
Gareth Southgate watched on as he scored his first two international goals against Kosovo on Tuesday, and Heskey thinks Sancho has more than justified his decision to leave City.
“English football and Gareth will end up owing a debt to Jadon Sancho,” Heskey told the Mirror. “A lot of young players were looking for someone to make a break for it and leave a big club to play first-team football.
“If he had stayed at City would he be in Pep Guardiola’s first team? Maybe. Would he be in the England side? No. Now he’s an integral part of the national squad. He’s not far behind Marcus Rashford, if he is behind him. But it’s thanks to the risk Jadon took – he went out on a limb.
“When it happened, people were looking at him thinking: ‘What has he done that for?’ Or: ‘He must be a trouble-maker’. He backed himself. He backed his talent and now it’s paying off for him.”
Heskey spent the majority of his career playing in England, though he has spoken of the enjoyment he found in spending two years with Australia’s Newcastle Jets.
The 62-cap forward is clearly now a big believer in young talent leaving the confines of England’s biggest clubs in search of game time – and thinks more should consider playing overseas.
“Think about the England team that won the Under-17s World Cup. How many of them are playing regular first-team football here? Phil Foden, now and again. Callum Hudson-Odoi will play for Chelsea, but that’s about it.
“Jadon has given the opportunity for young lads to be looked at. They can aspire to be in the first team at the age of 20 – but they know now that they have to go and play.
“Take Bobby Duncan, for instance. Look at the fuss he has kicked up at Liverpool. They are a massive club, the quality is very high. But he can’t be sat there at the age of 19 and not play. You have got to play games.
“At the age of 21 I’d played three-and-a-half seasons in the Premier League. They are wasting away. But Jadon has shown others the way.”