SYDNEY, Dec 2 (Reuters) - Australia opener Usman Khawaja has been ruled out of the second Ashes test against England in Brisbane later this week due to a back problem, the team said on Tuesday.

Khawaja was unable to open either innings in the series opener in Perth because of back spasms and showed some discomfort on Monday in the nets at Brisbane's Gabba ground, where the second test starts on Thursday.