The Belgium international has been a hit with the supporters since joining the club in a £15 million deal from Standard Liege in 2008 under Everton manager David Moyes.
But now the 25-year-old has emerged as a world star with Manchester United linked with a move for the player by The Metro last month, while Chelsea and Arsenal were credited with an interest by the Daily Mail.
Fellaini has become more of a goalscoring threat for Everton this season, which will add to his value when the club do sell him.
The Belgian has been employed in a role behind striker Nikica Jelavic this season, a different option from his preferred position in a more defensive role. But the switch has benefited the player and his club.
Fellaini may not see himself as a goalscorer, but his strikes against Manchester United, Sunderland and Arsenal so far this season came from the head, right foot and left peg respectively. This boy can clearly find the net.
And that's a pretty handy asset for an Everton side which is missing the goal threat that was once Jelavic.
With the Croatia striker failing to find his goalscoring form in recent weeks, the attention has turned to the likes of Fellaini for a cutting edge.
The Belgian scored twice in the 3-3 draw with Aston Villa at the weekend, his first goals in five appearances for the Blues.
But it is his physical presence which causes consternation for several teams, as Manchester United will testify after his bullish display in the 1-0 win at Goodison Park on the first weekend of the season.
Fellaini is also playing deep enough off the front line to shrug off the unwanted attentions of a central defender, while also allowing him the time to play balls out wide to the likes of Steven Pienaar and Leighton Baines to cultivate creativity.
Fellaini's increased profile has also seen him become a target for marking during matches, drawing at least two men to him and allowing greater space for Everton to exploit.
His excellent control of the ball with his feet and chest make him a perfect foil for containing the ball before deploying it to the wider areas where Everton are so dangerous.
Fellaini is likely to be heading out of the exit door at Goodison over the next year, but the emergence of his game on Merseyside will not be quickly forgotten.