Marco Silva has been sacked as manager of Watford after an "unwarranted approach" for his services came in from an unnamed Premier League rival.
The Hornets released a statement on their website confirming that the approach had "jeopardised" Silva's long-term stability at Vicarage Road.
Everton were linked with the 40-year-old Portuguese manager at the end of last year after the Toffees sacked Ronald Koeman, but the club went on to appoint Sam Allardyce.
"The club is convinced the appointment of [Marco] Silva was the right one and had it not been for the unwarranted approach by a Premier League rival for his services we would have continued to prosper under his leadership," the statement read.
"The catalyst for this decision is that unwarranted approach, something which the Board believes has seen a significant deterioration in both focus and results to the point where the long-term future of Watford FC has been jeopardised.
"For the security and success of the football club, the Board believes it has to make a change."
The club also confirmed that it will seek to make a "swift appointment" as the Hornets look for a replacement in the dugout.
Silva's last game in charge was Watford's 2-0 defeat to Leicester City at the King Power Stadium, which left the club in 10th position in the top flight.
The Hornets are five points clear of the relegation zone and face Southampton in the FA Cup fourth round next Saturday, before crucial Premier League games against Stoke City, Chelsea and West Ham United.
