The full-back picked up his fifth booking of the season during the first half of the Fratton Park victory and automatically serves a one-match ban.
He’ll therefore miss the midweek trip to Sincil Bank – handing Cowley a selection poser as the Blues look to extend their seven-match unbeaten run.
Among his options to fill the void are Connor Ogilvie – who has formed a solid partnership with Sean Raggett in the heart of the defence – Kieron Freeman, academy youngster Harvey Hughes and even Reeco Hackett.
But one player Cowley will reluctantly overlook is his maiden Fratton Park signing.
Vincent arrived at the very start of the summer from Bromley but is yet to feature for his new side after suffering a stress fracture in his leg during his second training session at the club.
But despite rating the youngster highly, Cowley confessed he’ll be looking for other solutions to his Brown problem.
When asked who could fill his boots and whether Vincent fitted the bill, Cowley said: ‘Liam's young and he's been training regularly and he's going to be a good player – a very good player – but it will be a big ask for Liam for us to throw him in without a game.
‘I know how tough it is to go to Sincil Bank, so we'll have to try to look at it and find some solutions.’
When quizzed further in who he could turn to, Cowley joked: ‘I’ve got loads of left-back available!
‘We'll have to train one up.’
And when asked if Hackett was an option, he added: ‘Yeah, that's one. We'll see’.