Usman Khawaja will remain with Australia's ODI squad this weekend and will not be available for the Sydney Thunder's crucial KFC Big Bash League derby against the Sixers on Saturday.

Khawaja was drafted in to Australia's squad after the first Victoria Bitter ODI on Tuesday as a replacement for opener David Warner, who returned home to Sydney for the birth of his second child.

Warner's position in the XI for the second match of the series in Brisbane yesterday was taken by Shaun Marsh, leaving Khawaja to fulfil 12th man duties.

Despite not playing at the Gabba and unlikely to be included for the third match in Melbourne on Sunday, Khawaja will not be released for the Thunder's clash with the Sixers in line with Cricket Australia's policy that Australia's squad members remain with the touring party during limited overs series.

It means the Thunder, who must win Saturday night's match to have any chance of reaching the BBL finals for the first time, will be without two of their star players after South African allrounder Jacques Kallis was also ruled out due to injury.

WATCH: Khawaja dazzles for Thunder

While it's not impossible for Khawaja to be in Sydney in time for the Thunder's match on Saturday night and then in Melbourne for the third ODI on Sunday afternoon, the short turnaround between the BBL clash and Sunday's match is considered too short by CA to be practical.

While Australia have regularly released reserve players from Test duties if they were not required in the XI, it's a practice deemed too complicated - both logistically and from a player management point of view - to work for one-day matches.

Releasing Khawaja would have potentially left Australia a batsman short for the MCG clash if one of their squad was ruled out at the last moment.

The danger of taking such a risk was exposed on Thursday night, when South Africa wicketkeeper Quinton de Kock was a late withdrawal from the third Test against England due to a freak injury he suffered while walking his dogs on the eve of the match.

It meant his replacement Dane Vilas had to embark on a 1000-kilometre journey from Port Elizabeth to Johannesburg, where he arrived an hour after play had begun.

Khawaja staying with the squad also means he will fly just once over the weekend instead of twice, another factor in CA's thinking when it comes to player management as shown by the resting of Mitchell Marsh this week.

As is the case every year, Australia's international commitments mean several BBL clubs are without some of their best players for the run to the finals.

But Melbourne Renegades captain Aaron Finch said last week that choosing to play for his country over his BBL franchise was always an easy decision to make.

"I’m disappointed that I can’t play that return leg but at the same time I would never give up playing cricket for Australia," Finch said.

WATCH: Finch in fine form for Renegades

"It’s just a part of cricket, when guys get selected for Australia it’s great for the Renegades.

"Unfortunately sometimes it hurts us on the scoreboard and on the ladder but we’re all very proud of anyone who plays for Australia and it’s a small sacrifice to make."

Speaking before confirmation of Khawaja's unavailability for the BBL was confirmed, Thunder captain and former Australia batsman Mike Hussey said he would be disappointed if the 29-year-old wasn't made available for his club and didn't play for Australia over the weekend.

"I would be (disappointed). He's obviously a crucial player for us," he said.

"I understand it's fantastic for him to be selected in the Australian squad and I think that's got to take priority - whatever's best for the Australian team.

"But if he's not playing and doesn't look like playing, then we'd love to have him back tomorrow.

"He's contracted to Cricket Australia - that's their call. They want to do the best by the Australian team but you also hope they want to do the best by us as well."