Borussia Mönchengladbach's Moritz Nicolas has a release clause in his contract valid for this summer, according to Sky Germany.
As far as Sky is aware, any of the top five clubs in the Bundesliga can activate it, with the clause costing between €10-15 million.
However, the same price range does not apply to Premier League clubs -- those from the English topflight have to pay €15 million.
With the future of Argentine shot-stopper Emiliano Martinez up in the air, Aston Villa recently expressed interest.
A summer transfer for Nicolas, who kept 13 clean sheets in 34 Bundesliga last season, could become a reality this summer.
