Shakhtar Donetsk have rejected an offer from Brighton for Mykola Matviyenko.
The Daily Mail says Brighton have had an opening 10m offer rejected Matviyenko.
The south coast club have been in talks with their Ukrainian counterparts in recent days and have now made a formal bid for the 26-year-old.
However, they appear to have fallen some way short of Shakhtar's valuation of the player, who are holding out for a fee in excess of 20m.
Brighton are keen to add cover in defence after losing Levi Colwill to injury last week.
The promising centre-back is expected be out for up to six weeks with a muscle problem.