Leeds United have offered a long-term contract to Josko Gvardiol as they close in on signing him from Dinamo Zagreb, Football Insider has learned.

The Premier League new boys are working on a deal to make the the 18-year-old their second centre-back signing of the window following the arrival of Robin Koch.

A Leeds source has told Football Insider that negotiations to finalise the capture of Gvardiol are progressing well and there is confidence among all parties he can be signed ahead of the new season starting at the weekend.

United are ready to hand the Croatia Under-21 international a big pay hike to lure him to Yorkshire as well as pay a fee worth up to £18million including add-ons.

It is a vast expenditure for a teenager playing in a relatively minor league but Leeds are convinced by Gvardiol’s potential.

Marcelo Bielsa has earmarked the youngster to provide cover and competition at centre-back as well as an option to fill in at left-back.

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Leeds have been in the market for a new left-back this window but have yet to strengthen in the position.

Gvardiol is in line to become Leeds’ third major new signing this summer following Koch and striker Rodrigo Moreno.

United have also signed Jack Harrison on a third consecutive loan and converted the 2019-20 loans of Helder Costa and Illan Meslier into permanent transfers.

Leeds want to bolster their defence line after winning the Championship title with one of the smallest squads in the league.

They failed to sign 2019-20 loan star Ben White from Brighton permanently but are now close to a second new defensive arrival to complement first choices Liam Cooper, Luke Ayling and Stuart Dallas.

Once Leeds are confident they have an agreement in place for Gvardiol, Pascal Struijk is then set for a season-long loan with Huddersfield Town one potential option.

In other news, Leeds United have set their sights on alternative new signing after forward pursuit collapses.