Dani Pedrosa will miss Sunday's British MotoGP as he continues to recover from a broken collarbone.
The Repsol Honda rider suffered the injury in Le Mans last month and also missed last weekend's race in Catalunya.
American rider Colin Edwards confirmed on Monday that he plans to race with a similar injury but Pedrosa has decided he is not fit.
He said: "I need to feel 100% fit before I get on the bike again."
The 25-year-old broke his left collarbone at the end of last season and after this year's opening race in Qatar complained of numbness in his arm.
That turned out to be caused by a metal plate inserted over the winter and once this was removed he promptly won the next race in Portugal.
But he then suffered another setback in the French Grand Prix in May when he crashed after a collision with Marco Simoncelli and fractured his right collarbone.
He is already 37 points adrift of series leader Jorge Lorenzo but is determined not to aggravate the injury by returning too soon.
"After dedicating some time entirely to recover, I have decided not to take part in the British Grand Prix this week," he said.
"I've done everything I could to be fit in time for Silverstone but the conditions are not right to return to compete with guarantees.
"I don't want to go out there just to do laps. I've raced many times with pain and the experience tells me I'm still not ready to be competitive.
"I've decided not to take further risks and will instead continue my recovery."