When Cheika included Pocock in the squad for Australia's final match of a dismal year, the coach conceded that the player who aggravated a long-standing neck injury against Italy last weekend was not 100 percent fit.
"Well I wouldn't say fully, no, I'd rather be fair and square about that, otherwise he would've been training today, wouldn't he? He's hurting but he's desperate to play," Cheika told reporters in London on Thursday.
"(But) I won't take a risk with him physically. If there was ever a risk, if he said he couldn't do it, then obviously not.
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"But he's telling me he can get there. He's done a few things which he's felt alright with, between more off-field stuff and a little bit of light stuff on field. So, I think he'll be right."
If Australia's previous 12 tests this year are anything to go by, however, the chance of the 23 players Cheika named on Thursday taking to the pitch for the anthems on Saturday is less than 50-50.
The Wallabies have made changes to their match-day squad after the team announcement in seven of those tests, indicating that Cheika is quite happy to give players as much time as possible to prove their fitness.
While Pocock was the only injury doubt in the squad this week, there has also been a stomach bug in the camp resulting in the added setback of illness in the lead up to the test.
If any of the backline are unable to run out on Saturday, it could lead to a reprieve for the versatile Kurtley Beale, who was a shock omission from the original squad.
The Wallabies will be wearing a special shirt with an indigenous pattern on it for only the second time, a touch that is very important to Beale, who is extremely proud of his Aboriginal heritage.
England coach Eddie Jones suggested that concerns over Pocock's fitness might simply be a case of his former Randwick club mate Cheika indulging in mind games.
Cheika was confident that regardless of the nagging injury, Pocock would still be a pest to England at the breakdown.
"He's had them at him all year," Cheika said. "He puts his head into places people (won't) go to, and he's copped a fair few whacks in there this year.
"So, he's certainly not scared to keep putting his head there. Hopefully it'll get looked after when he's in there.
"He definitely gets targeted, I can't say illegally..."
Australia have a poor recent record against England, losing the last five matches between the sides since the Wallabies recorded a famous win at Twickenham during the 2015 Rugby World Cup.
(Writing by Nick Mulvenney in Sydney; Editing by John O'Brien)
