Sakon Yamamoto will not be driving in Singapore this weekend because he has food poisoning, HRT team boss Colin Kolles said before Friday's initial evening practice practice.

Sakon Yamamoto will not be driving in Singapore this weekend because he has food poisoning, HRT team boss Colin Kolles said before Friday's initial evening practice practice.

The Japanese driver, who due to his powerful Japanese sponsors replaced team regular Karun Chandhok earlier this season, will be replaced by Christian Klien.

Austrian Klien, 27, a former Honda and BMW test driver, is the struggling Spanish team's reserve driver, with almost 50 grands prix of experience with Jaguar and Red Bull.

Despite saying he thinks Yamamoto has food poisoning, Kolles said he cannot guarantee the 28-year-old will be recovered by his home race in Japan in two weeks.

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