The 23-year-old centre-back missed Monday's 2-0 loss at Carrow Road with a knee injury.
Okore previously missed the first four months of this season after undergoing knee surgery in the summer, having battle through the pain barrier during last term’s run-in to help Villa beat the drop.
The 23-year-old centre-back eventually returned to first-team duty to start the 1-1 draw at Southampton earlier this month in the absence of the injured Micah Richards and suspended Ciaran Clark and impressed enough to keep his place in the side for the following three games.
However, the Denmark international has since been back on the treatment table after suffering further knee trouble in the 1-1 home draw with West Ham United on Boxing Day and missed the subsequent trip to Carrow Road as a result.
Skipper Richards returned from his own knee issues to partner the recalled Clark in central defence for the loss, with Joleon Lescott dropped to the bench, and it now remains to be seen whether Okore will be back to challenge them for a starting spot in time for Saturday’s match at fellow strugglers Sunderland.
“His knee was injured. I don't know how serious,” Garde said on Okore’s absence. “As the game took place very soon after the last one, he had a swollen knee and couldn't play.
“I made some other changes today to try and be a little bit fresher. It's always difficult to play 48 hours after.
“But it was not enough today.”
There is certainly an argument to be made that Okore is Villa’s best centre-back when fully fit, but persistent knee injuries have continued to disrupt his progress since he arrived at the club from Danish Superliga side FC Nordsjaelland in June 2013.
His absence was clearly felt at Norwich, however, as Richard and Clark were both woefully exposed at times, and having impressed over the previous four games, he deserves to be back in the line-up as soon as he is 100 per cent again.