Fiat Yamaha's Valentino Rossi admitted that he continues to have a nagging shoulder problem, though whether he'll opt for surgery remains unknown.The world champion injured the shoulder in a motocross accident back in April. The severity of the injury was initially downplayed, with Rossi only belatedly acknowledging the discomfort and effect on his riding. Since winning the season-opener in Qatar, Rossi hasn't been able to get to the top of the box and hasn't seriously challenged for wins. Part of that was due to the broken leg he suffered in his home race at Mugello. But even well after that he continued to complain about the shoulder.At a Dainese promotional event earlier this week, Rossi was heard telling fellow legend Giacomo Agostini that the shoulder would need surgery. Asked about it at today's pre-race press conference for the inaugural Aragon Grand Prix in Spain, Rossi said, "Yes, unfortunately the situation of the shoulder is not very positive, because one month ago we were very positive about don't do the surgery, but unfortunately I have pain and after the race in Misano I spent two or three days with a lot, a lot of pain. Now I'm not in a hurry, because I have to do the next six races that will be the test for understand if I will do the surgery during the winter or not."Having the surgery during the winter will have a profound impact on how quickly Rossi can shape the Ducati Desmosedici GP11 he'll be campaigning next year into a race. Despite some easing of the testing rules, there are limited opportunities to test if Rossi is going to make the bike his own.