The Belgian’s rejected terms for a new contract proposed by the club back in September and would be free to speak with other clubs in January ahead of a free transfer in the summer.
Mourinho has publicly made note of Fellaini’s importance to the squad and will be determined to fend off interest from the likes of Galatasaray, Besiktas and Arsenal, with the latter reportedly entering the race for his signature last week.
And Mills, speaking on BBC Radio Five Live, made it clear that Mourinho could not let Fellaini join a rival club on a free transfer.
“Why would you get rid of him? If you could keep him, why would you allow one of your rivals to take him and make them stronger?” he asked rhetorically.
“He does a job. He does what John Obi Mikel did for many years at Chelsea. Keep him and bring somebody else in as well. That would be the ideal scenario.
“It is not like ‘if we keep him, we haven’t got any money left because we’ve got to pay him some wages’. You keep him, allow him to do his job. Fill in when necessary, be a squad player, do all those things.
“He’s scored some important goals because he is a threat. Arsenal would love him, without a shadow of a doubt. Just to sit in front of the back four, win a few headers.”
The 54-year-old has spent enough time in the Premier League – and indeed at the highest level in general – to know that selling one of your most important players to a rival club for free is nothing short of managerial suicide.
Fellaini’s future is still decidedly uncertain. Whether he is holding out for a larger sum of cash, or simply wants to open a new chapter in his career, remains anybody’s guess. But if nothing else, Mourinho cannot let a player so crucial to his attacking dynamic join a side that would – let’s face it – benefit hugely from his presence in the box.