Ricky Ponting's men, keen to avenge their Twenty20 semi-final defeat, have taken a 2-0 lead in the seven-match series after game one was abandoned due to rain.
The reverses have put senior batsmen Sachin Tendulkar, Rahul Dravid and Saurav Ganguly under pressure after a young side achieved the Twenty20 success in their absence.
Chief selector Dilip Vengsarkar said patience might run out on the senior players after Tendulkar made 0, 16 and 43, Dravid 31 and 0 and Ganguly missed out due to injury.
"Definitely, the threshold has reduced. No question about it," he was quoted as saying in the Mid-Day tabloid, when asked whether selectors would be patient with the senior players.
He said young batsmen such as S.Badrinath and Suresh Raina were doing well for India A.
"These guys are waiting for their chance and you cannot ignore them," he said. "It's a professional set-up and nobody can take their place for granted," he added.
The fourth one-dayer will be played in Chandigarh on Monday while the fifth will be played in Baroda on Friday. India recalled left-arm spinner Murali Karthik in place of inconsistent Ramesh Powar for the fourth and fifth ODIs.
Colonel justifying the move said: "If you get picked as a frontline bowler, then you have to bowl 10 overs. Plus, if your fielding is found wanting and you do not contribute with the bat, the team is obviously at a disadvantage. Ramesh has to get fitter and field better. He also has to improve his bowling."
He also justified Kartik's selection ahead of promising Hyderabad and India-A left-arm spinner Pragyan Ojha. "Ojha is very young, just 21. It is not fair to unleash him against a side like Australia. We need to groom youngsters. Kartik is experienced and offers us better variation than two offspinners."
The Indian board said after the team's shock first-round exit at the one-day World Cup in March that they would focus on youth.
The board secretary Niranjan Shan fuelled speculation over Ganguly's absence in Friday's 47-run loss when he said he was dropped although he had recovered from a hamstring strain.
Indian fans are hoping their team's fortunes improve soon with Pakistan due to arrive for a Test and one-day series.