The Brazil Under-17 captain is being strongly linked with a move to Everton.
But, speaking to Talksport earlier, Vickery warned those of an Everton persuasion not to expect Reinier to revolutionise their first-team squad if he joins from Flamengo.
According to Globo Esporte, Everton will resume talks to sign the 17-year-old - whose family expect him to move to an albeit unnamed club soon - in August.
And Vickery said: "He really would be one for the future. He’s not a first-team player yet. He was on the bench on Sunday, really because they had an injury crisis. They’ve got a huge game today. He may get a look-in. But as it stands he’s under-17 player. He’s not a first-team player.
"He does have huge promise. He reminds me a little bit of a Brazilian Michael Ballack. He’s that kind of midfielder. But that means, in terms of adaptation, I think it would be harder for him than it was a couple of years ago for Vinicius Junior, who went off to Real Madrid at a similar age. Vinicius Junior had much more first-team experience than Reinier Junior has, which is absolutely none. But the thing that Vinicius has, that works wherever you play football, is that unbelievable pace and acceleration - the sixth gear that he’s got.
"With Reinier Junior the adaptation will be harder when he does come across, because in Brazil with the defensive lines playing very deep, players in his position have a lot of time to make a decision on what they’re going to do. They can receive the ball, wander a little bit, read the newspaper and only then make the decision of what pass to make. Now, in European football with the lines much closer together - and several of the playmakers who’ve gone over, they all complain about this - it's much, much harder because you have much less time to make a decision. So anyway, a lot of fuss about him.
"But if Everton are to buy him and he does get the clearance and all the rest of it, don’t expect him to revolutionise the first team just yet."
Globo Esporte claims that Reinier - who wouldn't be able to move abroad until his 18th birthday in January - is likely to cost any would-be buyer close to €35 million (around £32m).
Everton could soon find themselves short in Reinier's position, with the futures of James McCarthy, Morgan Schneiderlin, Muhamed Besic and Joe Williams uncertain.
The Toffees sold Idrissa Gueye to Paris Saint-Germain earlier this week, but have effectively replaced the Senegalese midfielder with Fabian Delph already.
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