Australian captain Michael Clarke is a serious doubt for Wednesday's final one-day international against Sri Lanka after twisting his ankle.
He was undergoing treatment, Cricket Australia said, ahead of the game Australia need to win to draw the series 2-2.
Clarke went over on the ankle during a fielding drill at training on Tuesday.
George Bailey, who would stand in as skipper, said Clarke would be given until the last minute to decide.
"He will obviously be given right up to the toss tomorrow to prove he is right to go," Bailey said.
"There will be a little bit of pain but, if he is 100 per cent, he will play."
All-rounder Glenn Maxwell was expected to be promoted if Clarke fails to recover.
Sri Lanka lead the five-match series 2-1 after the fourth leg in Sydney was washed out on Sunday.
The tourists were chasing 223 runs to take the series after thrashing Australia in the second and third games. They needed 209 more runs off 46.4 overs with all their wickets intact when the umpires took the players off.
Australia scored 222 for nine off their 50 overs after winning the toss.
Follow Emirates 24|7 on Google News.