Marlboro Ducati's Casey Stoner will re-join his MotoGP team at Estoril after taking an enforced break of three races in order to examine a mystery illness which has been identified as low blood pressure and low sodium levels.

The Aussie is not in peak physical fitness and will remain under medical supervision throughout the weekend while also sticking to a sodium-rich diet. Doctors blamed overtraining for his exhaustion.

"Having three races off is the biggest period away from racing in my life. It was very difficult to accept the advice of the doctors to stop racing. In the past I have raced even when injured, like in the last few races of the 2008 season when my wrist was broken, but this time it was really not possible and of course I felt very sorry for the team," said Stoner.

"Now I’m looking forward to getting back together with the team and everyone and I hope I’ll be able to be more competitive than I was in the past, but we will have to wait and see. The doctors have put me on some salt tablets to increase my sodium levels but we will have to see if it helps.

"We will understand more during the weekend. Of course it’s going to be difficult: at first we won’t know if it will work because I’ve been off the bike so long that in any case my muscles will take some time to get race fit again. But, as I said, I’m looking forward to getting back and to starting work on the bike, looking towards the future.”