Michael Clarke's left hamstring injury is believed to be serious enough to rule him out of the entire limited-overs portion of Australia's looming West Indies tour. He is therefore set to miss Thursday's third tri-series final against Sri Lanka.

After leading his side to an eight-wicket defeat in the second final in Adelaide, Clarke said he was unsure of the extent of the strain that affected him during his century in the afternoon. He took the field in the evening as the Sri Lankans drew level.

Clarke was due to undergo scans on his hamstring on Wednesday, however ESPNcricinfo understands the strain is likely to be serious enough to rule him out for up to four weeks, putting the captain in a fight to be fit for the Test matches in the Caribbean, and certain to miss the ODIs. The first Test will begin in Barbados on April 7.

This scenario leaves the vice-captain Shane Watson to lead Australia in the West Indies for the early part of the tour, with Clarke's arrival possibly delayed to allow him time to recuperate at home.

Mickey Arthur, the Australia coach, confirmed Clarke would be missing from the early part of the West Indies tour, though the results of the scans were yet to be known. However Arthur defended the decision to rush Clarke back into the team for the triangular series finals.

"It doesn't look great for certainly the early part of the one-day series in the West Indies," Arthur said. "In your round robin phases it's obviously about building a base and giving opportunities. But when you get to the finals, we were always prepared to risk a player in order to win a final. So I certainly think it was worth the risk."

Arthur pointed out that while Clarke had missed numerous ODIs across his career due to injury, he had always been fit to play Tests, not missing a single match due to injury since his debut in 2004.

"I'd have to say Michael is the most professional guy I've certainly seen in my time in terms of the way he manages his body [and] the way he goes about his treatment," Arthur said. "He is very methodical and very professional, so he's got every chance to keep getting it right.

"We were just looking through the stats last night, funnily enough, when we were having a chat. I think Mike has missed 15 ODIs through injury [and] he hasn't missed a Test yet. That's a pretty good record so no area for concern just yet. He's always on top of his game and he's always making sure he's looking after that department."

George Bailey and Nathan Lyon, both slated to travel to the Caribbean, have been called in as reinforcements for the third final against Sri Lanka on Thursday.

Clarke's is not the only injury problem for Australia, with the fast bowler James Pattinson also missing the third final due to a glute strain he picked up while fielding. The injury took place only three matches into Pattinson's return from the foot stress injury that shortened his Test summer.

"James Pattinson's done a little bit of a glute, he's also having a scan, so James Pattinson will not be playing tomorrow," Arthur said. "Patto's first [injury] was a stress fracture of the foot, which is just caused by excessive use on hard wickets, and last night he dived for a ball on the boundary and just pulled a glute, he's done something and that'll probably be seven to ten days, not serious but we need to get it scanned."

Edited by Brydon Coverdale