Makoto Tamada could be forced onto the sidelines for the fourth time this season after getting caught up in a big accident during the opening World Superbike race of the weekend at Imola.

The Japanese rider crashed five laps into the opening race when he was taken out by wild-card rider Luca Conforti at the final corner chicane.

Banging his head in the impact, although Tamada was not knocked unconscious in the smash, he admits he cannot remember what happened.

Forcing him to miss the second race too, with the next round of the season at Magny-Cours this coming weekend, Tamada admits his knock to the head could force him to sit out another event - his eighth of the year.

"I have once again had terrible bad luck during the weekend which started in qualifying. I was unlucky to miss my fastest lap which would have got me into Superpole and I was taken out midway through race one by an Italian wild card rider on the last chicane which meant I didn't finish any races again.

"The only lucky thing from this weekend is that I wasn't seriously injured as this was a very big crash and I don't remember a thing. I'm not 100 per cent sure if I will be able to ride at Magny-Cours as I have had several injuries to the head this season so I'm feeling very disheartened and I really hope that I get some luck to finish off the season on a higher note."

Tamada has been on the receiving end of several injury problems in 2009 following a series of mishaps, including at Losil when a crash in warm-up meant he failed to start either race, at Monza when an accident left him with an injured wrist and a recovery period of five rounds and then most recently at the Nurburgring when he was taken to hospital with concussion courtesy of a fall shortly into the first race.