He decided to fight back after a dip in form had seen Louis Deacon take his place.
And on Sunday, against the All Blacks, Kay will run out at Twickenham as vice-captain, the man in possession of the shirt once more as England launch their run-up to the World Cup.
He puts his rejuvenation down to a chat with Leicester forwards coach and former England hooker Richard Cockerill.
Kay said: "He told me 'I didn't think you'd get back. I thought you'd lost it.' So I had to prove the poisoned dwarf wrong.
"I went home and wrote down everything I had to do to improve. It boiled down to me being a bit more selfish and demanding the ball more.
"It snowballed from there. Now I don't worry if I don't get picked. I'm much more relaxed."
It also taught him to enjoy life and shed his renowned intensity.
He added: "I was determined to start enjoying my life outside rugby. I was getting caught up in worrying too much.
"I wouldn't go out before a match. I used to turn down social occasions, thinking I always needed to put my feet up.
"But Martin Corry (England's captain) told me to say 'Yes' more and I try to do that now and I am more happy. I enjoy a glass of wine and I am playing better for it."
So much so that England head coach Andy Robinson made Kay one of his three vice-captains, a tribute to his regard for a man who links up with Danny Grewcock once more on Sunday in England's first choice second row.
Kay said: "Making me vice-captain is Robbo's way of making sure I pull my weight as a senior player. It means Corry has someone to bounce things off.
"I am looking forward to renewing my partnership with Grewy (Danny Grewcock). Our styles complement each other."
Kay is not one of those who regard New Zealand's decision to rest some of their top players as a snub, especially as he finds himself up against Gary Jack, a man who would slot comfortably into most people's World 15.
Instead he said: "There is a great atmosphere in the camp. You cannot recreate Test rugby on the training pitch but I am confident with the guys I will be running out with."