Stade Reims have ambushed Middlesbrough's deal for Heerenveen winger Mitchell Van Bergen, as reported by Football Insider.

On Saturday, it had emerged that Neil Warnock's side had a deal in place for the 21-year-old and had his medical booked, but it appears that Van Bergen will be heading to France.

The latest report states that the Netherlands U21-international is keen on a move to France's Ligue 1.

Boro have made nine signings this summer, in a window where the club have equipped themselves for what is expected to be a top-six challenge.

Van Bergen, who joined Heerenveen in 2018, is one game shy of 100 appearances for the Dutch side, scoring 17 and assisting a further 10 during that time.

The young winger played the full 90 minutes in Heerenveen's season opener against Go Ahead Eagles, but was an unused substitute on Saturday against RKC Waalwijk - the day news emerged that Middlesbrough were on the verge of signing him.

The verdict

This is undoubtedly a blow for Middlesbrough. Van Bergen would have posed a constant attacking threat, and he had the ability to operate on both flanks.

It remains to be seen whether or not Warnock's men delve back into the market in what remains of the transfer window, but it would be no surprise to see Boro target another young winger, who would be ready to step into the first-team environment.

Van Bergen seems like an exciting talent and it will be interesting to see how his move to France's top division will pan out.

Middlesbrough have built a strong squad that is capable of operating at the top end of the Championship this season, and whilst the signing of the young winger would have bolstered the club's attacking options, it is certainly not an urgent area of improvement.