Australia have left out injured fast bowler Ryan Harris and batsman Usman Khawaja for the third and final cricket Test against Sri Lanka starting in Colombo on Friday.

Usman Khawaja

Harris, the most successful bowler in the series with 11 wickets, suffered a hamstring strain during the drawn second Test in Pallekele, and will be replaced by Peter Siddle.

Left-handed Khawaja was dropped to make way for former captain Ricky Ponting, who returns to the side after taking leave from the Pallekele Test for the birth of his second child.

Skipper Michael Clarke and the selectors had a tricky decision to make after Shaun Marsh, who replaced Ponting in the second Test, scored a century on debut to cement his place in the side.

"It's brilliant to have Ricky back, he was always going to walk back into the team," Clarke said ahead of a practice session at the Sinhalese Sports Club (SSC) yesterday.

Clarke said resting Harris was a precautionary measure considering the heavy schedule ahead, which includes Test series against South Africa, New Zealand and India.

Clarke said Australia's 1-0 lead in the series after winning the opening Test in Galle by 125 runs had put the onus on Sri Lanka to call the shots. "There is probably a bit more pressure on the Sri Lankans,"  said Clarke yesterday.