Former Republic of Ireland international Kenny Cunningham believes Robbie Brady's injury is a massive blow for club and country.
The Burnley man has torn his patellar tendon and will be out for the rest of the season.
The Clarets manager Sean Dyche confirmed the extent of the injury on Wednesday saying: “Robbie will have surgery to repair a patellar tendon tear and will be out for a substantial recovery period.
“He will be given all the time and care he needs on his recovery and supported throughout from all of us at Burnley Football Club.”
Reports indicate the knee injury will keep him sidelined for between 4-6 months.
Brady has been crucial to the Clarets good start to the Premier League season, he's played in all 15 of their games so far - starting and finishing 13 of them.
The 25-year-old netted his first goal of the season against Bournemouth two weeks ago, as they edged the game 2-1.
Burnley currently occupy 7th spot in the Premier League table having won 7 of their 15 games so far this season
Speaking on OfftheBall.com’s new weekday breakfast video show OTB:am, former Ireland captain Kenny Cunningham said mental recovery from a long term injury is as tough as physical recovery.
“It’s a shame, I knew he had the injury and knew he had a reasonably bad one but I was hoping it wouldn’t be that serious.
“Any long term injury just psychologically and mentally Robbie has to get his head around it quickly and crack on, I’ve noticed now in the game that the initial first couple of weeks are key like.
“As opposed to when I first came into the game long term injury was almost, not a jolly but took the players two months [to adjust] to get the head right.
“You’ve really got to be so focused straight away even before you have the operation people are in getting their muscle definition up, it’s important to do the work before as opposed to after.
“I wish him the best of luck, we need him back fit going forward.”