Watford have enquired about Sunderland midfielder Didier Ndong.
The 23-year-old cost Sunderland £13.6m when he joined from Lorient but Watford will be hoping to get him for around £8m.
The Gabon international has barely figured this season and last played in the 1-1 draw with Birmingham City last month.
Watford have Will Hughes out through injury so want to strengthen in this window.