Everton manager David Moyes has been forced to use makeshift options in the fullback positions so far this season.
Ratcliffe told the Liverpool Echo: “I look at other teams, other full-backs and other centre-backs and I look at Jake O’Brien and he’s done exceptionally well, he’s been brilliant. But he’s not a right-back.
“I think Jake has been one of our star players this calendar year, but modern day full-backs do bomb on and they’re playing like an added winger with the wide attacking players tucking in. As well as he’s done and he’s great at getting in around the back post sometimes and he looks dangerous, I think we need someone with a right-back brain.
“At some point I think Jake will move back into central defence. At the moment I think Michael Keane is playing better than James Tarkowski, even though you know what you get from Tarky.
“Michael has been excellent in terms of the way he’s responded to coming back into the team. But we do struggle when Vitalii Mykolenko is missing at left-back as we haven’t got another left footer to play there.
“These have got to be things that we’ve got to be looking to improve upon to get better as a team. I don’t want to be disparaging about Mykolenko, but you’ve always got to be looking at bringing in better players than what you’ve currently got.
“You should be looking at getting better than Jack Grealish in. Even though you’ve just brought him in, you should be thinking: ‘We’ve got him for this season, what are we going to do next year?’
“If we can’t get him or can’t afford him, there’s a decision to make, but you should be looking in every position. We shouldn’t be having to make do with sticking people outside their natural roles to cover, like James Garner who can come in and do a job, but again, he’s not a left-back and to be fair I quite like him in midfield, he’s got that energy, although sometimes his team-mates don’t follow him and back him up.”