Watford have been linked with a surprise move for Sunderland defender Younes Kaboul.
The 30-year-old, who has become a key figure in the Sunderland defence, joined the club from Tottenham Hotspur last summer for a fee of £3million.
But Premier League rivals Watford are reported to be weighing up a move for the Frenchman, with French newspaper L’Équipe claiming the Hornets are keen to sign Kaboul on a three-year deal.
Kaboul has struck up a strong central defensive partnership with Lamine Kone - who is wanted by Everton - since the Ivory Coast international arrived at the Stadium of Light in January.
Their form was a key reason behind the club's survival last season, with both starting against Manchester City on the opening day of the Premier League season.
Moyes was asked about Kone's future at the weekend and he stressed he was keen to keep those players who make a big contribution to the team.
Moyes said: "The big thing is, we are short of players, whether it be centre-halves or midfield players or full-backs, we are short. I won’t be letting anybody go who I think can contribute to the team.
"Kone is a big contribution to the team.
"If I think I can do things in other ways, I will think about it, but, at the moment, the market has made it really difficult to do that."