Hartman revealed on Goedemorgen Eredivisie that Chelsea had concrete interest in him and had already contacted to Feyenoord.

"In the last winter break it had started. Then they came to Feyenoord, but there was already talk that I didn't want it myself at that time. I had only just broken through and then only just started playing everything for six months. Also with the Dutch eleven, with the European Championship coming up..."

Hartman was badly injured against FC Utrecht on March 31st and suffered a serious knee injury, which means he will miss the upcoming European Championship. "I would have gone anyway, I spoke to him of course," Hartman said of Koeman and the Euros.

"Whether I would have played, I don't know. But I secretly think I would have. In the system we play there I think that would have fitted well and I've also shown it in games with Oranje, so that's galling yes."

Hartman made his Feyenoord debut in August 2022 in an away game at RKC Waalwijk (0-1 win) and was hardly out of the starting line-up after that. On 29 August 2023, the left-back extended his contract at Feyenoord until mid-2026.

"From Feyenoord it was also clear that we were open to it in the summer, but not at all then. Last month it came back again and they really wanted me, I was definitely open to it as well, but yes... Now unfortunately things have turned out differently, but yes. But at the same time: staying with Feyenoord is also fine by me."

'Interest doesn't stop'

When asked by columnist Sjoerd Mossou whether a move to Chelsea was a sensible move for a boy his age, Hartman did have an answer ready.

"Chelsea is a club with a lot of young players, with a plan for the next few years how they want to go about it. I understand for someone out there that you see it that way because they also buy new players easily, but at the same time I think if you play very well yourself, then you are going to play."

"If you don't play well, then maybe someone else will come in your place. Then we are talking about the Premier League and a club with the ability to buy any player in the world."

Whether Chelsea have had any contact with Hartman after his injury: "Yes, they have wished him good luck and said that the interest does not stop."