Sky Sports sources understand that Newcastle United have made a bid for Watford defender Adrian Mariappa.
The 25-year-old has emerged as one of the stand-out defenders in the Championship over the last 12 months.
Swansea City showed an interest last summer and were linked with a renewed bid this January.
However, Newcastle have now emerged as favourites to claim his signature after making a move for his services.
Newcastle are in need of defensive cover having lost Steven Taylor for the season.
Mariappa, who has come through the youth ranks at Vicarage Road, has 18 months left on his current contract.