Clarke fitness battle as Aussies face pace choice

Skipper Michael Clarke is racing the clock to be fit for the Boxing Day Test against Sri Lanka as selectors mull whether Mitchell Johnson or Jackson Bird will be Australia's third pace bowler.
Clarke has been treating a right hamstring strain suffered in Australia's 137-run win over the tourists in last week's first Test at Hobart, while Johnson and Bird were added to the squad for the injured Ben Hilfenhaus.
Selectors have placed Usman Khawaja on standby for Clarke, with vice-captain Shane Watson expected to lead the Australians if the skipper fails in his fitness bid.
Clarke, who has reclaimed the top spot in the latest ICC Test batsman rankings, said last week his scans were "positive" and he was confident of playing. He has been having an extraordinary season, scoring 1,489 runs at 106.35 and is just 55 runs adrift of Ricky Ponting's Australian record of 1,544 in a calendar year with a potential two innings left in Wednesday's Melbourne Test.
Opinion is divided over the merits of left-armer Johnson and newcomer Bird for the third pace spot alongside Peter Siddle and Mitchell Starc.
Australia's greatest Test wicket-taker Shane Warne has plumped for Bird, who has excelled in the last two Sheffield Shield seasons and is ideally suited to the Melbourne Cricket Ground. Starc's 24 Test wickets have come at 29.20 while Johnson has taken 196 wickets in his 48 Tests at 31.17.
Bird has built a strong case for selection with 80 wickets in his 14 Sheffield Shield matches for Tasmania at 17.54 and has snared 14 of those in two matches at the MCG at 12.07.
Australia largely dominated Sri Lanka in Hobart with Siddle and Starc leading them to their first win of the home season, after losing to South Africa 1-0 in the recent three-Test series.
Sri Lanka have yet to win in Australia in 11 Tests, going back to 1988 and struggled in the fast bowling department in Hobart, relying on spinner Rangana Herath to take the wickets late in the game. Herath is expecting vocal support from the large expat Sri Lankan community in Melbourne for the team's first Boxing Day Test at the MCG in 17 years.