"I had no intention or desire to leave the club this summer," he said.
"I've had things to resolve in my private life but I felt I had sorted everything out.
I love the club so much, in fact, that I'd spoken to friends recently about staying on for another year and ending my career in Glasgow. But this has knocked me for six.
"All I can do now is discuss with my agent what happens next and I'll do that in the coming days.
But right now I need some time to digest what has just happened. It has come as a bombshell."