Brisbane: With Michael Hussey announcing his intention to quit international cricket just weeks after ex-captain Ricky Ponting retired, Australia's attention has turned quickly to who will fill the two big voids in the batting order for 2013 series in India and England.The 37-year-old Hussey, seemingly at the peak of his powers, made the surprise announcement on the weekend as Australia prepared for the third Test in a series they have already secured against Sri Lanka by winning the first two matches.The traditional New Year's Test at Sydney starting January 3 will be Hussey's 79th and last, following Ponting - Australia's all-time leading run-scorer - into retirement.Phil Hughes, a 24-year-old top-order batsman who has been in and out of the national line-up since scoring hundreds in both innings of his second Test against South Africa in 2009, has been earmarked to continue batting at No. 3 after replacing Ponting for the Sri Lanka series, with Pakistan-born Usman Khawaja likely to move into the Test squad as a contender to bat at No. 5 or No. 6 after being on standby for skipper Michael Clarke in recent Tests.Hussey nominated his brother, 35-year-old David Hussey, among the contenders to bat for Australia in India and in the Ashes. "I'm not worried about the team whatsoever," Hussey said on Sunday. "We've got some fantastic candidates to come in â probably too many to name. Maybe David Hussey could get a run â one Hussey out, one Hussey in. History has shown players have come and gone. But the game continues to move forward, and it'll be no different with me."Michael Hussey didn't make his Test debut until he was 30 but has been a valuable contributor to the team, accumulating enough runs to be 12th on Australia's all-time list of run-scorers. His supreme fitness has helped him forge a strong middle-order combination with Clarke across the last year, the pair frequently combining after failures from the top order.Now it'll be left to Clarke, who has excelled as a batsman and captain since replacing Ponting in 2011, to work with an inexperienced line-up as Australia face the challenge of touring India in February and March and then face England away and at home in back-to-back Ashes series.Glenn Maxwell, a young off-spinning allrounder from Victoria state who has been drafted into the 13-man squad for the Sydney Test, discarded Rob Quiney and Tasmania's Alex Doolan are all being touted as possible Test batsmen of the future.Mitchell Starc, a tall, left-arm fast bowler who is just establishing his credentials in the Test arena, said he was surprised at the sudden nature of Hussey's retirement. "He's still in great form with the bat, as we've seen through this summer so far," Starc told Australian Associated Press on Sunday from Sydney. "He's going out the way he wants by the sound of things and it's going to leave a big hole. It's hard to replace Ricky Ponting â now we've got to replace him and Mike Hussey, so it's a big gap."Hussey has scored 19 centuries in 78 Tests and averages 51.52. His recent form has been strong and he's averaging 180.00 after two Tests in the current series against Sri Lanka with scores of 115 not out, 31 not out and 34 in Hobart and Melbourne.Hussey, nicknamed 'Mr. Cricket' because of his career-long dedication to the game, said that with four children under eight, it was time to spend more time at home.Hussey is Australia's 12th-leading run-scorer with 6,183 runs at 51.52. His retirement follows the Test departure last month of ex-skipper Ricky Ponting, Australia's all-time leading run-scorer.Cricket Australia said later in a statement that Hussey will play out the remainder of the 2012-13 Australian summer season, as well as be available for Western Australia state."Michael Hussey has been a vital contributor to many Australian team wins over his very successful Test cricket career," Cricket Australia chief executive James Sutherland said. "He has always been thoroughly committed to meticulous preparation and the highest levels of physical fitness which have in turn delivered consistent performances in all forms of the game."