Coutinho played for Brazil in midweek – but he’s yet to feature for Liverpool this term due to a reported back injury.
Despite his desire to leave Anfield, Barnes reckons Coutinho will be focussed on getting selected for the Etihad clash.
“Jurgen Klopp is so in command of that club, the player have to fall into line,” Barnes told the Daily Star.
“As much as Coutinho wanted to leave, the move hasn’t come about.
“I know Coutinho a little bit. He’s a good character and while he wanted to go to Barcelona he’ll knuckle down and perform.
“I think he’ll feature, I’m sure he’ll be involved in the squad and he’ll be OK.”