The 26-year-old suffered cruciate ligament damage during his side's 1-1 draw with Championship leaders Burnley on Saturday and will play no further part this campaign.
He told the club's official website: "I wanted to take this opportunity to express my gratitude to every fan who has offered me their support since the news broke of the severity of my injury. The amount of messages I've been sent is extremely humbling.
"Playing football is my favourite thing in the world. That might seem easy to say but I think anyone who has seen me train or play knows that to be true. I don't care how it comes across, I genuinely love it. To not be able to do it for so long is going to be so tough, and to be honest it probably hasn't sunk in yet.
"But when you get the kind of support I have from fans, friends and family it makes the long road that little bit easier. It's an amazing feeling and it keeps me motivated.
"I would also like to express my thanks to the owners and all staff at Nottingham Forest. Their support truly proves how united this club is at the moment.
"I expect to be at the Reading game on Friday night and will be supporting the lads all the way."