Keane was stretchered off in Wednesday's game against Fulham last weekend, but Gray has revealed that the damage wasn't as bad as first feared.
There was an initial scare that the Manchester United loanee could have damaged his ankle ligaments, but it seems that the injury is much less severe.
“He’s had his MRI scan," Gray explained in the Sheffield Star. "The results have not shown any major damage.
“His ankle is swollen and there is slight ligament damage in his ankle. He’s not going to be fit for Saturday. Hopefully he will be back training with us after the international break.”
Keane has been Wednesday's main source of goals of late and his return to the first-team will be an undoubted boost for the side.
The striker looks a real talent and his pace allows the Owls to stretch defences, which helps make more space for the team's more creative outlets.
Zayatte has been back in training after missing nearly a months worth of action, while Bus could be fit to play for the Yorkshire side's development squad next week.