The 23-year-old made a welcome return in last month's Capital One Cup defeat at Manchester United, almost exactly a year after being sidelined by a cruciate knee injury.
He suffered a minor setback after that game but insists he is now recovered and awaiting his opportunity.
"You have to have a lot of patience in football as well as knowing when you are given your chance you have to take it," he said.
"It has taken a long time to get back to full fitness. I feel really strong physically now and I am biding my time to get my chance and grab it with both hands.
"It has taught me to look after myself in terms of what my body needs to cope with demands of the Premier League and over the past 12 months (I've been) getting myself to a physical condition which will cater for that and I'm raring to go to get that chance."
Kelly has had a couple of outings for the under-21s to help him get up to speed and that has been beneficial.
"From a development (point of view) and confidence in terms of my knee it has been fantastic," he added.
"It is much more difficult playing in the Premier League and Capital One Cup than reserve team level.
"I've done those few games as a physical aspect and I'm glad they've had me. It has been vital for my rehab.