Prior sustained the injury during the tour match against Australia A in Hobart and was ruled out of the ongoing game against the Australian Invitational XI at the SCG.
However, in a webchat with readers on the Daily Telegraph website on Friday morning, Prior had positive news about his fitness, revealing he has even been able to take part in a net session.
He said: "Rehab on the injury is going well and it's improving everyday. I was even allowed to leave the trusty ice machine to hit some balls in the nets today!!! Signs are good so fingers well and truly crossed."
With Prior absent, Jonny Bairstow took over the gloves for the current match in Sydney as England continue their preparations for the first Ashes Test, which starts in Brisbane on November 21.
Asked his thoughts on the Yorkshireman's skills behind the stumps, Prior said: "The 'keepers' always have to stick together especially on tour.
"It's been great working with Jonny as we push each other to improve and that can only be good for both of us.
"I'm a big believer in team mates helping each other out rather than seeing each other as competition or anything else like that. At the end of the day we are a team and it will be the team effort that wins the Ashes not a group of individuals."