The Belgian midfielder is a regular starter at Goodison Park, and at 22, represents one of their most valuable assets.
With the club currently in financial turmoil, with a messy ownership situation and two Profitability and Sustainability breaches hanging over them, Everton are likely to sell this summer.
Spanish outlet Sport claim that Barca are one of the clubs keen on signing Onana, but much would need to change for them to afford the young midfielder.
With Everton believed to value Onana at £60m, Barcelona's own financial troubles means this is an unlikely figure for them to afford.
Unless there are many outgoings from the club, Barca may only be able to offer something in the region of €40m (£34m), a fee not too dissimilar to what Everton paid Lille for the player 18 months ago.
The sale of Raphinha could help fund a potential move, but the club are also keen to make Joao Cancelo and Joao Felix's loan moves permanent, which will also command a notable fee.
The report states that Barca's sporting director Deco is a big fan of the player though, and sees him as someone who can add physicality to a midfield that is somewhat lacking that at present.
Pedri, Gavi and Frenkie de Jong are all of a similar profile, and Ilkay Gundogan is not a player they can build the midfield around, given his age.
Manager Xavi preferred a technical midfield trio as opposed to adding any strength and height, but with his departure at the end of the season now confirmed, Deco is believed to be moving ahead with building his own Barcelona team.
Despite Everton's financial difficulties, they are unlikely
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