Pocock is racing the clock to be fit in time to play Scotland in the quarter-final at Twickenham on Sunday (Monday morning AEDT) and will have scans in the coming days on his calf.

But it could have been much worse when footage emerged of Pocock trying to free himself from a ruck when Wales hooker Scott Baldwin was cynically holding him back.

Striking an opponent with your knee carries a penalty between 4-12 weeks. But while citing commissioner Steve Hinds deemed Pocock was in breach of Law 10.4(a), it was decided the incident only warranted a warning and off-field yellow card.

Pocock raised his knee to try to break free as he was held behind the play.

Ireland flanker Sean O'Brien was involved in a similar incident 24 hours later, but he lashed out and punched France lock Pascal Pape in the stomach, which is set to see him suspended.

Cheika joked he'd tell his players to hold Pocock back as well if he was coaching against him.

But he was adamant officials were doing a good job of stamping out the under-handed tactic.

"It goes in swings and roundabouts, those types of things," Cheika said.

"I personally feel that those things have been dealt with relatively well. There's clear instructions, I think the referees on the field are doing the same. They're refereeing the tournament really well and clearly.

"Most things are getting picked up … [Pocock] got held a bit [against] Fiji as well. But if I was coaching against him I'd probably try to hold him as well."

The Wallabies are keeping a close eye on Pocock's progress after he was forced to leave the field in the second half against Wales.

Wallabies medical staff delayed sending Pocock for a scan until the bleeding stopped so they could get a clearer indication of how serious his injury was.

Israel Folau (ankle) and Matt Giteau (ribs) are also under injury clouds, but rated likely starters against Scotland. Michael Hooper is also due back after serving a one-match suspension.

"With [Pocock's] mentality he could probably be ready tomorrow," Cheika said.

"We'll just let it play out, we'll let it follow its course with the medics and go from there.

"They don't think [there's a tear], he couldn't remember it. [There's] no resting, this is not the time to rest.

"Obviously he's got to be able to perform and we don't want to get him further injured. It's the normal risk assessment that goes on for any game with any player."

The Wallabies were given the past two days off training to allow them to physically and mentally recover.

Players spent the days after beating Wales exploring London and getting ready to move their base from the city centre to closer to Twickenham.

Meanwhile, Ross Ford and Jonny Gray are in danger of missing Scotland's World Cup quarter-final against Australia after both were cited for foul play.

First choice hooker Ford and lock Gray, who forms an effective partnership with older brother Richie, have been cited for a lifting tackle during Scotland's thrilling 36-33 win over Samoa on Saturday.

Their hearing will take place in London on Tuesday morning (Tuesday night AEDT) and will be heard by English lawyer Christopher Quinlan.

WORLD CUP QUARTER FINALS

Quarter final one: South Africa v Wales at Twickenham, 2am Sunday AEDT.

Quarter final two: New Zealand v France at Cardiff, 6am Sunday AEDT.

Quarter final three: Ireland v Argentina at Cardiff, 11pm Sunday AEDT.

Quarter final four: Australia v Scotland at Twickenham, 2am Monday AEDT.