Wednesday 26 November at 18:00 : Nov.26 (GMM) Red Bull boss Christian Horner has ruled out calling up David Coulthard to substitute for the injured Mark Webber at next month's Jerez test

He said Coulthard, whose fiancee Karen Minier gave birth to their first son in Belgium last week, "has a lot of other duties at the moment"

Horner is quoted as saying by The Sun that the Milton Keynes-based squad's winter development programme will not be overly affected by Australian Webber's broken leg

"If there is anything positive in Mark's accident, it is the timing," he said, referring to the more than 120 days until the first race of 2009

Filling in for 32-year-old Webber at the other Jerez test, the last of 2008 late in December, will be test driver Sebastien Buemi, who is likely to race with Toro Rosso next year, and New Zealand teenager Brendon Hartley

For F3 driver Hartley, who has only just turned 19, it will be his first proper test, following shakedown duties for Red Bull and its sister team Toro Rosso

"Brendon is one of the shining lights in the (Red Bull) junior team and an opportunity has arisen to allow him to get some time in a formula one car," Horner said