Former manager David Moyes is reportedly interested in taking the left-back to Old Trafford, who scored seven times and assisted a further six last season.
As revealed by Goal earlier in June, Arsenal activated Fellaini’s €26 million buy-out clause before upping their contract offer last week, but Ratcliffe feels Baines would provide the bigger void in the Everton squad.
|5/6||Wayne Rooney is 5/6 with William Hill to stay at Manchester United this summer
"His free kicks and set pieces in and around the box are quality, and he’s improved massively as a defender as well.
"He’s a proven international now, he’s battling it out with Cole for the number one left-back spot for England, so he’ll be a big miss.
United are reported to have failed with a €14m bid for Baines, with the club insisting the England international is not for sale, but Ratcliffe believes €18 million will see Moyes reunited with the left-back.
"I would have thought the club would be looking for around the £15m mark if he was to leave," Ratcliffe continued. "I think if the right offer comes in Everton will take it and I think an improved bid of around €18m might sway things Manchester United’s way.
"If Everton get the right money it may be right for both parties to part company, especially because of his age. It's unlikely they'll get this much money for him two or three years down the line. But that’s only if the player wants to go."