Is Marco Melandri injured? If you follow the Italian's postings on his Twitter page the answer was no. But now it seems to be yes.On December 17, Melandri worte "waiting for shoulder scan... big pain with no reason, that's weird."On December 20, Melandri wrote "Everything is going good... just getting old. Need to be back on my R1 as soon as possible!Now things look grim again for Melandri, at least according to today's Tweet."Bad present for Christmas... For sure better now then (sic) in a month... Hope to be ready for round 1."Melandri has signed to race for the Yamaha World Superbike team in 2011, joining Eugene Laverty on the factory R1s.On December 23, Melandri confirmed that he had indeed undergone shoulder surgery with a post on his Twitter pag: "Surgery on rt shoulder went well... long way to wrok to be fit at round 1."