In a big setback to Australia, skipper Michael Clarke and fast bowler James Pattinson have been ruled out of the series-deciding tri-series final against Sri Lanka on Thursday, due to injuries.

Australia coach Mickey Arthur said Pattinson has strained a buttock muscle, while Clarke has injured his left hamstring and will miss the third final to be played at the Adelaide Oval.

Pattinson will undergo some scans later in the day and so will skipper Clarke.

The danger of missing the West Indies tour, for which the team will leave on Friday, is looming large on Clarke.

Arthur said the extent of Clarke's hamstring strain remained unknown.

"It doesn't look great for certainly the early part of the One-Day series in the West Indies," Arthur told reporters.

Pattinson strained a glute muscle while diving in the field during Australia's loss to the Sri Lankans in Wednesday's second final in Adelaide.

Australia have been grappling with injuries to many key players with opener David Warner and paceman Brett Lee also among the injured list but they continued to play in the series.