From the conductor’s site:
Andris Nelsons withdraws from his upcoming performances with the Royal Concertgebouw Orchestra (December 11, 18 and 20, 2015), on Doctor’s orders, with an acute shoulder strain issue. Mr Nelsons will have complete rest from conducting duties for a number of consecutive weeks, whilst receiving a course of physiotherapy. Mr Nelsons is expected to make a full recovery, returning to the podium in January 2016.
He won’t be doing any of this