Dirk Nowitzki wants to represent his homeland, Germany, in the World Championships this summer, writes Dwain Price of the Star Telegram.  But, his coach Don Nelson thinks he should skip the event to deal with nagging injuries.  Nowitzki has bone spurs in his ankles Nelson thinks should be removed with surgery as soon as the Mavs postseason is over.  Nowitzki is reluctant to have surgery unless the problem becomes severe.