"I was impatient but the manager told me I had to be patient," Fletcher told the Telegraph.
"When you have been out for a long time you are desperate to play so maybe you do push yourself, but I had good people around me like the sports science staff, the manager and the reserve manager Warren Joyce.
"They were there with the reins on me, holding me back. Deep down, I always knew they were right but it is hard to accept because you are desperate to get back as quickly as possible.
"I feel great, but when you have been out for a long time it is going to take time before you are 100 per cent."