Ashwin wasn't part of India's World Cup squad picked by the selectors earlier this month.
Akshar suffered a left quadriceps strain in India’s Super 4 match against Bangladesh on Friday (September 15) and was ruled out of the Asia Cup final.
Washington Sundar was picked by the selection committee as Akshar’s replacement, and the Tamil Nadu all-rounder also featured in the summit clash.
"Akshar had a small tear. It looks like maybe it will take a week or 10 days (to heal), I don’t know. We have to see how that injury progresses. Some guys recover quickly, and I hope that’s the case with him," Rohit said in the post-match presser.
"I am not sure whether he will be able to play the first two games against Australia at home. But we will wait and see," he added.
India will host Australia in a three-match ODI series from September 22 to September 27. This series will give the Men in Blue another opportunity to fine-tune their preparations before the ODI World Cup, slated to get underway on October 5 in India.
Talking about Shreyas Iyer, he picked up a back spasm ahead of India's Super 4 game against Pakistan and didn’t take part in the remainder of the continental tournament.
Rohit said Shreyas did not tick off certain parameters and, thus, he was not considered in the playing XI for the Asia Cup final against Sri Lanka.
"Shreyas was not available for this game because certain parameters were kept for him to tick off. I think today, he completed most of it. I should say he is alright 99 percent as of now. But he looks good, he batted and fielded for long hours, and he was on the ground long before we came to the ground. I don't think it is a worry for us," he remarked.
Even though Washington was named in the Indian squad as a replacement for Akshar, Rohit revealed that veteran off-spinner R Ashwin is in the scheme of things as well.
"As a spinner-all-rounder, Ashwin is in the line. I have been talking to him on the phone. The injury happened to Akshar at the last minute. Washington was available, so he had to come and perform the role for us," the Indian captain said.
"He (Washington) was cricket-fit because he was part of the Asian Games camp (in Bengaluru). I have been very clear with players about their roles. Everyone is in the loop," he further stated.
India will open their ODI World Cup campaign against Australia in Chennai on October 8.
(With PTI Inputs)