2007 world champion Casey Stoner will, as planned, return to MotoGP action at this weekend's Estoril round, following a three-race absence due to mystery fatigue problems.
After an impressive opening five rounds, which saw Stoner leading the world championship with two race wins, the Ducati star struggled with sickness at Barcelona (round six) and then fatigue at the next four races.
Tests proved inconclusive and, after returning home to Australia for further medical advice during the summer break, it was announced that Stoner would miss the next three rounds to try and recover.
Doctors now believe that low blood pressure and a lack of sodium were behind Stoner's problems, with overtraining and past injuries also a factor.
'During two months away from racing under the supervision of an expert medical team in his homeland... Casey has undergone a series of exams and special tests,” said a Ducati statement confirming Stoner's return to action.
'The results of the tests have excluded pathological anomalies of cardiovascular, respiratory or neurological origins. The exams and inspections also failed to show up any kind of virus or infection.
'However, the medical report made by Prof. Silderberg [Cardiologist] and Dr Coleman [Consultant Physician] did reveal low blood pressure levels and a lack of sodium, the two factors that the doctors believe were the main cause of the physical problems that interrupted the season for the Ducati rider.
'The doctors all agree that overtraining was the most common factor that showed up during the tests and that the after-effects of injuries and surgeries over the last few years were the cause of the physical weakness and exhaustion that the Australian began to suffer a few months ago.
'The doctors also unanimously confirmed that their suggestion to stop Casey from racing at the end of July was absolutely necessary in order to avoid aggravating his physical debilitation.