Liberatore was accidentally kicked in the head by opponent Conor Nash late in Sunday's upset loss to Hawthorn at Marvel Stadium.
The defeat leaves the Dogs' season on the brink at 3-5.
Liberatore needed help as he left the field, his face covered in blood.
It was his first game back after collapsing on the field during the round-six loss to Essendon, with the Bulldogs later confirming that was also because of concussion.
They released a statement on Monday afternoon, confirming Liberatore is sidelined again.
Tom Liberatore leaves the field bloodied during the loss to Hawthorn. (Morgan Hancock/AAP PHOTOS)
"Having suffered two concussions within a short space of time, Tom will be unavailable for an indefinite period as the club works through a thorough process before a return-to-play plan is determined," the Bulldogs said.
Sunday's defeat, punctuated by some dreadful errors in defence, ramps up the pressure on coach Luke Beveridge, who is enduring a bad few days.
Last week, Essendon ruckman Sam Draper said several Bulldogs players would leave at the end of the season if Beveridge remained coach.
That earned Draper a sharp public rebuke from his coach Brad Scott, while Beveridge called the comments bizarre.
Nevertheless, Beveridge is well aware the Bulldogs are now firmly in the media spotlight following the Hawthorn loss.
"We know that unless you're winning games of footy, you're always vulnerable to media scrutiny, so we just expect it," the Bulldogs' 2016 premiership coach said.
"As I've said before, I have a thick skin and can deal with it, but I won't let it affect how I care for and manage the playing group.
"Any external scrutiny, we just have to deal with."
Bulldogs coach Luke Beveridge leaves the huddle at Marvel Stadium. (Morgan Hancock/AAP PHOTOS)
Beveridge has made a succession of major selection calls this season, with Bailey Dale and Rory Lobb again dropped for Sunday's match.
Earlier on Monday, Bulldogs president Kylie Watson-Wheeler noted that Beveridge is contracted until the end of the season and called for calm.
"I think it's too early in the season for us to panic or for us to make rash decisions," Watson-Wheeler told ABC Radio.
"But we're always coming together as a club and we're always discussing where we're at. Does the playing group have what they need? Are the right decisions being made?"
"This is not something that you just jump in on when you have a bad loss … these conversations are happening constantly and we're always assessing where we are at as a club."
Meanwhile, Liberatore's tackle on Will Day earned him a one-game ban for rough conduct, but it is irrelevant given he is sidelined already for their must-win match next Saturday night against Richmond.
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