Casey Stoner faces a crucial test of his fitness ahead of his return to MotoGP racing at the Japanese Grand Prix, six weeks after surgery to his right ankle.
The two-time world champion will assess his recovery from ligament surgery in opening practice sessions at the Motegi circuit.
He has missed the past three races because of the injury he sustained during qualifying for the Indianapolis GP in August. He is now out of contention to retain the title, which will be decided between his teammate Dani Pedrosa and Yamaha rival Jorge Lorenzo.
He admits it has not been easy recuperating while watching Pedrosa and Lorenzo battle for the title. "The last six weeks have been pretty tough for me. I've had to sit around and rest my ankle, get some physio and try to occupy my time, but I've been watching the races at home."
The demands of Motegi, with its areas of hard braking and acceleration, will be a tough test for Stoner's return.
It is the first step in his campaign to be fully fit for his home race, the Australian GP at Phillip Island, in two weeks.
"Motegi is pretty tough on the body. The first session will be crucial to see how my ankle feels in the boot and the degree of movement I have and pressure I can apply."
Before the surgery to repair seriously torn ligaments, Stoner feared he may not have a full range of movement and strength in his ankle. His last race appearance was eight weeks ago with a brave fourth place, riding with pain killing injections and an oversize boot for his swollen ankle, in Indianapolis.
Stoner is third with 186 points having won four races. Lorenzo leads the championship from Pedrosa, 290 points to 257, with four races remaining.
Stoner is due to retire from MotoGP at the end of this season in Valencia in November.