Kenya’s Olympic 800m champion David Rudisha is facing a three-week lay-off with injury, sending the east African nation into panic mode and sparking fears over Rudisha’s challenge at the World Championships.

Rudisha picked up a knee injury running in Central Park in New York City, undermining his preparations for August’s worlds in Moscow.

“He was jogging inside Central Park when he realised something was the matter with his knee,” Colm O’Connell, the Irish high school teacher who coaches Rudisha, said.

“Two initial investigations were done, first in the USA and also in Germany, and we decided that he takes a three-week rest.”

He will definitely miss Kenya’s National Championships, which start in Nairobi tomorrow, but his participation in the World Championships is not expected to be in doubt, even though he might be forced to sit out Kenya’s trials.

“We are not sure yet whether he will be ready by the time of the trials,” O’Connell said.

“But being a world champion, we are expecting that he will get an automatic selection (known as a wildcard) to the worlds.

“He does not need to run at the trials to be selected. He will only run if he feels comfortable.

“We were already panicking, but we were assured by medical specialists after the second scan that he does not need an operation. But he needs between two to three weeks to rest.”

Rudisha, 24, who won the Olympic title in a world record time of 1:40.91 in London last year, ran a season leading 1:43.87 in the first IAAF Diamond League meeting this year, in Doha last month.