Everton's managerial search took a blow on Monday evening, as they failed with an approach for Watford boss Marco Silva, according to BBC Sport.
Koeman's 16-month stint at Goodison Park is now over, but with caretaker boss David Unsworth winning just the once in his four games in charge, an external appointment could be on the cards.
However, Everton have failed with one bid for a new manager, as BBC Sport report that the Toffees have seen their approach for Watford's Marco Silva rejected by their Premier League rivals.
Silva, 40, took his first steps in English football by becoming Hull City boss in January of this year, and whilst he impressed in charge of the Tigers, he couldn't prevent their relegation to the Championship.
The Portuguese boss took over as Watford manager over the summer, and he has already impressed with the Hornets, though his early exploits at Vicarage Road haven't quite convinced Everton fans yet.
Toffees supporters have taken to Twitter to share their concerns over Silva's nomadic managerial career so far, having managed four clubs since the beginning of the 2014-15 campaign, with others suggesting that he would be a 'disaster' for Everton and just another Roberto Martinez.
Others hailed his man-management skills, claiming that he is just what Everton need right now, with something of a split in opinion between those who think Silva is perfect for the job, and those who want Everton to steer well clear.
Find it odd that #EFC seem keen on Silva but there's been no talk of Thomas Tuchel. Understand he's somewhat unknown but the two seem very similar to me.— Sean Lunt (@Sean_Lunt) November 13, 2017
Silva did well b4 coming over to PL, then nearly kept up a terrible Hull team while restoring Naisse confidence - Watford been doing well, and he is just 40! Has my backing if it happens— EFC (@MagooMr12) November 13, 2017
I can't say I'm particularly overwhelmed by the thought of Marco Silva as #EFC manager. Would be a dull appointment imo— Rob Smith (@Rob99Smith) November 13, 2017
Marco silva? What's our thinking behind getting players and now manager's who's only experience is getting relegated? Do we fancy a bash at winning the championship next season or something? #EFC #BackwardsThinking #WeNeedWinners— zak dunstan (@zakdunstan) November 13, 2017
Don't want Marco Silva if he's the the type of person to walk out on a club 11 games into a 2 year contract. Also comes from the Martinez school of relegation.— Paul EFC 86 (@PaulEFC86) November 13, 2017
The thought of Marco Silva doesn’t get my blood pumping with excitement; previously relegated & lost a 2-0 lead at Goodison with Watford.— Mathew (@Mightymj1) November 13, 2017
But ok...he’d get my support like all #EFC Managers.
Marco Silva to EFC: Alarm bells have to be ringing with a guy who's managed 5 teams in 4 years. More so if he abandons Watford for us— Lee Clough (@LeeClough) November 13, 2017
Marco Silva would be a perfect fit here at Everton, someone who will work hard and build a quick and powerful team, i'm hoping he'll be one that'll be here for a while and will want to push this club back into our glory days.— $lenderman (@EFCMatthew) November 13, 2017
Silva is a man manager. He gets the best from players because they buy into him and his ideas. Exactly what #EFC need.— David Downie (@daviddownie17) November 13, 2017
Silva will be Martinez 2.0 sorry— Vic (@victoriacarlin_) November 13, 2017