There's a bit of a clue at the end of his interview with Sandra on the OS - link
I hope for everyone's sake at the club not directly involved with the deal that they didn't know for long. Imagine if it had gotten out and that it was a possibility for a month, say, or even a week, that we could get him back - it would've been torture! Hoping with everything you've got that he'd re-sign for us, writing it off as something too good to happen to us, fearing that another club might swoop in and nab him from under our noses.
No. This way was much better. BANG! Totally out of the blue and then, done deal! Absolutely perfect! Now all there is left to do is worry that it all turns out even half as good as it promises to be!