Adelaide: A hamstring injury is hampering Australian captain Michael Clarke's prospects of being fit for this month's tour of the West Indies.Clarke will have scans on his left hamstring, which was strained while making 117 in Australia's loss in the second tri-series final against Sri Lanka in Adelaide on Tuesday.He will not be fit for Thursday's deciding final in the best-of-three series and could also be in doubt for the looming tour to the Caribbean.The Australian players are due to fly to the West Indies on Friday, with the opening ODI match at St Vincent on March 16."I have done something to my left hamstring, I don't know to what extent," Clarke told reporters after Tuesday's ODI loss. "But it's obviously not feeling good at the moment, that is for sure.""We leave for West Indies in three days. I don't want to make a judgment until I make a scan, I think I would be silly to do that."Clarke only returned to action last weekend from a strain to his right hamstring, which sidelined him for three games, and he has a history of lower back problems. And the captain admitted he went against the wishes of Australian team physiotherapist Alex Kountouris by returning so soon."It's a tough one, I pushed really hard to try and get back for this finals series," he said. "And I tried my best not to give Alex much of an option, to be honest. So I feel for him as well as my left leg at the moment because I know he probably would have preferred me to take it easy.""But I wanted to be part of this finals series. But after straining my right one, I probably favoured my left over the past couple of weeks, 10 days, and I have done a bit of damage there."His absence is a major setback for Australia, who have lost four of their last five ODIs against Sri Lanka.Australia coach Mickey Arthur said rushing Clarke back was worth the gamble. "When you get to the finals, we were always prepared to risk a player in order to win," Arthur said. "So I certainly think it was worth the risk."He 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.Allrounder and regular vice-captain Shane Watson led the Australians in the absence of Clarke immediately before the tri-series finals started, and former skipper Ricky Ponting led the team in two league matches during the tournament but has subsequently been told by selectors that he'll no longer be considered for ODI selection. Watson is just returning from almost three months on the sidelines with his own injuries, and hasn't returned in peak form.Clarke, who replaced Ponting as captain last April, was recently voted Australia's player of the year and has been in outstanding form with the bat in the one-day international and Test formats.Meanwhile, in another blow for the home team, fast bowler James Pattinson has also been ruled out of Thursday's series-deciding final at Adelaide Oval. Arthur said Pattinson has strained a buttock muscle. Pattinson strained a glute muscle while diving in the field during Australia's loss to the Sri Lankans on Tuesday and will also undergo some scans later in the day. Spinner Nathan Lyon is likely to replace James, with Peter Forrest tipped to take Clarke's place.Australia will play five one-day matches against the West Indies â the first three in Kingstown, St. Vincent on March 16, 18 and 20. The final two matches are scheduled for Gros Islet, St. Lucia on March 23 and 25.Australia and the West Indies will then play two Twenty20 internationals before the three-Test series starting April 7 at Bridgetown, Barbados.