Liverpool are ready to finally make an official offer for Schalke defender Kyriakos Papadopoulos after being assured that the centre-back's injury problems are now behind him.

The Greek international made just 10 league appearances for the German side last season but a report on the Bundesliga website confirmed that he is scheduled to return to training for the first time since a knee injury in November.

After having an operation on his knee just over seven months ago, Papadopoulous is hoping to be fit for the start of the new season and it seems Liverpool are now keen to test Schalke's resolve to hang on to the highly-rated defender.

The Express reports that Liverpool are willing to bid in the region of £13m as manager Brendan Rodgers looks to find a long-term replacement for Jamie Carragher.

Kolo Toure has already arrived but there is a lack of depth in the Liverpool squad as both Martin Skrtel and Sebastian Coates fell out of favour with Rodgers last season.

With reports in Italy suggesting that former Liverpool manager Rafa Benitez is interested in bringing Skrtel to Napoli, there could be even more need for the Reds to find a new partner for first choice centre-back Daniel Agger.

Benitez has already captured Pepe Reina on a season-long loan and it seems he is now keen to be reunited with Skrtel. The Slovakian fell badly out of favour under Rodgers in the second half of last season and there has been much speculation about his future.

Even if Liverpool retain the services of Skrtel they may well feel the need to sign a young centre-back who can remain at the club for many years to come. At just 21 years old Papadopoulous appears the perfect solution, but much will depend on whether Schalke are prepared to allow him to leave.

The former Olympiacos defender already has 16 caps to his name for Greece and just last summer rejected a move to Zenit St. Petersburg despite Schalke accepting an offer of £16m.