Watford boss Marco Silva fears losing star Brazilian Richarlison.
Richarlison, who has been a revelation since his £11.5million summer switch from Fluminense, is already attracting strong interest, says The Sun.
Tottenham and Chelsea and are among the Premier League clubs keen on the five-goal wideman.
Club from the Chinese Super League are also watching developments.
Silva said: "For us to improve as a club we need to sign players with ambition.
"I want everyone in the club to work hard and if they achieve something else in their careers, then that's normal. I'm realistic
"While they are at Watford they need to give 100 per cent.
"To do well in their careers is fantastic for us as a club and also for the player."