That's shocking news and weird timing, with rebuilding his next great team almost being complete!
If he told the club in November, he's obviously had a lot of time to make sure it's the right decision for him and his family before making it public.
Also weird that the whole coaching team is going as well. Have to assume the players were aware, and are making sure he gets the best send off ever!!
No-one is irreplaceable, but Jurgen comes pretty damn close to it! Let's hope the club already have someone (Xabi) lined up