BRAD HADDIN
The wicketkeeper is odds-on to lead Australia for the rest of the Border-Gavaskar series.
But, at 37, it’s unlikely he would continue in the role beyond the 2015 Ashes series.
If made permanent skipper, Haddin would become Australia’s 45th Test captain and the oldest to make his leadership debut since Jack Ryder in 1928.
If injuris did force Clarke into immediate retirement, could Haddin captain until, say the middle of next year, and then hand over to a younger leader?
SHANE WATSON
Australia’s 44th Test skipper, Shane Watson, led the team in Delhi last year, however his indifferent form with the bat and uncertain place at No. 3 would make him an unlikely candidate.
If Watson was a consistent and determined performer he'd be the obvious choice. But, frustratingly, he isn't one of those.
STEVE SMITH
Savvy Test watchers had pencilled Steve Smith in to be Clarke's successor as far back as two years ago.
Being a batsman from New South Wales means he certainly fits the mould.
His position is cemented in the middle order, which makes him the leading candidate for the long term.
The only downside is his lack of leadership experience, however in his limited experience he has done an excellent job, including leading the NSW Blues through the Sheffield Shield grand final last season and captaining Sydney Sixers.
DAVID WARNER
From what he has shown onfield in the past 12 months there is no reason why to suggest he wouldn't do a fine job.
The problem for Warner is that his off-field misdemeanours still count against him.
It was only 18 months ago that he punched Joe Root in the English pub and many of cricket's conservative cricket followers are yet to warm to his personality.
The Poms hated Ricky Ponting.....What would they think if Warner was the new Aussie captain!
PETER SIDDLE
While the 30-year-old has the work ethic and leadership skills to be considered, the fact he is a bowler means he won't be considered.
Plenty of other countries have enjoyed success under the leadership of a bowler but it's just not the way it works in Australia.
Is it too hard to manage the bowling attack when you are part of it?
There is also significant doubt over Siddle's position in the side.
The Victorian has been down on pace for the past 12 months and coach Darren Lehmann has been quoted saying Aussie Test bowlers must regularly hit at least 140km/h.