Gray told his blog on BBC Sport: "It's been a tough fortnight without a game and it's time to take off the running shoes and get the boots on again.
"The game against Derby County was put to bed early. After a long chat - and what I would call a video nasty - it was out on to the training ground to work our socks off.
"As you can imagine, the gaffer wasn't in the greatest of moods and neither were the lads. I'm not one for moping around and thinking the world is going to end. The best thing to do is get on to the training ground and work to put things right.
"And in fairness the lads have looked really sharp. Whatever the gaffer has asked of us we have gone out and done, which I'm sure he appreciates."