Clarke doubtful for tomorrow's match

Australia batsman and vice-captain Michael Clarke is doubtful for tomorrow's Commonwealth Bank Series decider against New Zealand due to a niggling back injury.

Clarke failed to train today, but skipper Ricky Ponting said his condition had improved and was optimistic his deputy would be able to fulfil his new duties at the top of the batting order.

"Michael Clarke didn't train today but that's not unusual for him, he generally doesn't do much on our optional days," Ponting said.