Australia coach Mickey Arthur has conceded captain Michael Clarke is in genuine doubt for the Boxing Day Test in Melbourne after suffering a hamstring strain on Monday.
Clarke retired hurt on 57 after a brief consultation with team physio Alex Kountouris as Australia made their way to a 392-run lead over Sri Lanka on day four in Hobart.
The skipper appeared to pull up short after running a single during his sizzling cameo knock - perhaps fortunate for Sri Lanka but potentially devastating for the Australian outfit given Clarke's career-best form and tactical nous.
Arthur suggested all-rounder Shane Watson would take on the top job should Clarke not recover in time for the second Test.
"It is a distinct possibility, it would be a really good challenge for Shane," Arthur said. "We'll learn a lot about Shane and his leadership ability. I'm confident he will come through it very well."
"If it (Clarke's absence) does materialise it will be a really good opportunity for him (Watson)."
Clarke's injury comes in the wake of a side strain suffered by paceman Ben Hilfenhaus on Sunday and is likely to mean the home side enter the biggest day on the Australian cricket calendar with a significantly altered line-up.
Arthur said Clarke would undergo scans in Hobart on Monday night and more would be known on Tuesday as to whether the in-form 31-year-old was likely to come up for Boxing Day.
If not, he nominated veteran keeper/batsman Brad Haddin as one of four potential replacements.
"There are possibilities. (Brad) Haddin is one of them, (Rob) Quiney's one of them and certainly Usman Khawaja is very much in the frame. Alex Doolan has played well, also," Arthur said.
Arthur also speculated on a couple of likely replacements for Hilfenhaus, the Tasmanian quick now likely to be sidelined for the rest of the series.
"All I can say is we've had a list of bowlers leading into our summer and we're well down the list at the moment. But it's going to be a fantastic opportunity for a couple of those guys," he said."The names on everyone's lips are guys like Jackson Bird, it could be Nathan Coulter-Nile, and that will form part of the discussions we have tonight."