The former Manchester City midfielder thinks it is a dream for the Brazilian to play at the Nou Camp.
And Barton also believes it is just a matter of time before Liverpool end up accepting a bid from Barca.
He said on talkSPORT: “He [Coutinho] wants out, and if you’re getting up to what are they now, almost £120m, it just looks like how much rather than if or when.
“He’s not a Scouser, he’s a Brazilian. He’s already living a fair distance away from home and he’s probably grown up wanting to play for Barcelona.
“No disrespect to Liverpool, but that’s the club Brazilian youngsters grow up wanting to play for nowadays.
“It’s not the Liverpool of the 80s, it’s Liverpool who haven’t won a title for over 20 years, so you can’t blame the boy.
“As I said, it’s just a case of how much and at what moment he goes.”
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Barton has also criticised Liverpool for not being prepared when having options to replace Coutinho if he does leave Anfield.
“Liverpool should have pre-empted this,” he added.
“They should have known a big club was going to come sniffing for him and, although he’s difficult to replace, they should have had replacements lined up for him.”
Coutinho has yet to feature for Liverpool this season because of injury.
The Reds return to action tomorrow night when they welcome Hoffenheim to Anfield in the second leg of their Champions League play-off round tie.
