The midfielder is eager to start training.
â€śItâ€™s been tough, a lot of time in the gym and a lot of time in the physio room and not playing football, something Iâ€™m not used to,â€ť he said.
â€śIâ€™ve never had an injury like that before. Iâ€™m still young, but itâ€™s the first injury Iâ€™ve had so I couldnâ€™t really enjoy not playing.
â€śI definitely am look forward to getting my boots back on and kicking a ball around again and getting back on the pitch and obviously in the Premier League, which is a big step up.
â€śSo itâ€™s a really exciting time in my career.â€ť
Butterfield, who has represented England Under-21s, has played twice at Carrow Road for his former club.
He said: â€śIâ€™ve played here a couple of times for Barnsley and there was always a fantastic atmosphere.
â€śThe pitch is lovely and weâ€™ll be looking to play some good football here. Iâ€™m just delighted to have it sorted and looking forward to getting into it.â€ť