Watford are rivalling West Ham with interest in Swansea defender Alfie Mawson, Sky Sports News understands.
The 23-year-old England U21 international is highly sought-after following a string of impressive displays, despite the Swans' struggles at the foot of the Premier League table.
LISTEN: Transfer Talk podcast
Listen to the latest Transfer Talk podcast where Ross Barkley's move to Chelsea and Philippe Coutinho's Liverpool future were among the topics discussed.
Sky Sports News reported last week that West Ham boss David Moyes is targeting a new centre-back during the January transfer window after losing Jose Fonte to injury in October.
West Ham want Mawson, who has 18 months left on his current contract, but Swansea do not want to sell him in the January window.
Mawson insisted in an exclusive interview with Sky Sports earlier this month that he was concentrating on the ongoing relegation battle and that talk of a transfer was just that - "talk".
He said: "Whatever happens, happens. If offers come in then that is nothing to do with me. All I can do is affect my performances. I'm a Swansea player and I want to do well here.
"It is flattering to hear certain things but I have got to do what I can for this club. I'm contracted for another two-and-a-half years after this, whether that is in the Championship or hopefully in the Premier League, I am signed to be here so that's all it is at the moment, it's just talk."