From Fishal site:
'Miller missed much of the second half of last season during his time at Celtic with a groin problem. He then missed United's tour of America having undergone surgery to cure the injury.
The Irish international has started in United's last two matches on the right of midfield - a position he has played on Republic of Ireland duty.
"I think I’ve settled in OK now," he told Manchester United Radio. "The players have been great with me. I’m really enjoying it.
"I had the operation in the summer, which was a success. And now I am back to feeling 100%," added the midfielder.
"The injury gave me problems when I was making sharp movements and restricted me when I was running. I’d missed much of the pre-season so I lost out on some hard work over the summer.
"That pre-season training is vital because it gets your fitness right for the games. It is the difference between having that extra bit of fitness and strength in games. But I think I have caught up with the rest of the lads in that sense now."
Recalling his decision to move south of the border, Miller says the choice to join United was an easy one, and has been vindicated by the step up in standards he has experienced.
"When a club as big as this comes calling there is only one answer," he said, thinking back to January earlier this year when United came in for him.
"I was delighted when I heard the news that Manchester United were interested. My mind was made up pretty soon after that.
"It’s different to Celtic in terms of the facilities and the training," he said. "The standards are higher here. It has just been a case of adapting to that, but I’m enjoying that side of it."'