That is the best-scenario return date to the World Cup for the All Black No 8.
Team doctor Deb Robinson said yesterday Read's type of injury usually meant a six-to-eight-week recovery, a time-frame which would cover the World Cup.
"However we are thinking that five weeks could get him back ready to play," she added.
"He will soon be back in camp with us and we will have him there for 24 hours a day and be able to treat his injury aggressively. The rest of his ankle appears to be in pristine condition."
Read's target date for a return would have him back for the All Blacks last pool game against Canada in Wellington in the first weekend in October.
Fellow loose forward Adam Thomson also had his left elbow injury scanned on Monday and his problem is not as serious as Read.
He has damaged the medial ligament in his arm and also suffered a muscle tear, injuries Dr Robinson thinks could repair for the opening World Cup game against Tonga in 10 days. She believes he is more likely to be given until the second match to fully recover.
"Adam tweaked his elbow first against the Springboks but it got better and then he reinjured it against the Wallabies and injured his upper arm.
"I have never seen that before and he could not recall what happened but he has got two parts to his injury," Dr Robinson said.
All Black injuries are nothing new for World Cup campaigns but Read and Thomson's damage bites into the loose forward resources.
At the 2007 tournament in France, lock Keith Robinson was unfit for the opening few rounds while in 2003 Ali Williams needed that time to fully recuperate from a foot problem.
In 1995, Zinzan and Robin Brooke were both injured but taken to the tournament in South Africa where they played after a couple of rounds while in 1991 loose forward Mike Brewer was excluded controversially, on medical grounds, when he failed a test on his injured foot.
Even if Read returns on October 2 against Canada, he will have little rugby to fall back on. His three months rugby tally since the Super 15 final is two full games and 12 minutes before he was replaced on Saturday.
"His departure in the 12th minute was a big loss as he weds the unlikely bedfellows of being erudite and aggressive - he's a bright bully," former Wallaby skipper John Eales observed.
Dr Robinson said the goal was to get Read back for the last pool game with Canada.
"Over the next few weeks we will see if that is realistic."
Forwards coach Steve Hansen said Richie McCaw, Jerome Kaino and Victor Vito would deal with the loose forward duties and if one of them was injured Sam Whitelock would be used.
The World Cup rules were clear.
If anyone was replaced in the squad they could not return, so Read and Thomson would be watching for a while.