The 30-year-old went under the knife for knee surgery on May 19, and is not expected back in training until autumn.
Despite travelling to Australia, Cooper has not featured in either of the Whites' pre-season fixtures. Cooper's injury isn't serious, and he does hope to be fit for the start of the Premier League season.
"I just have a little issue with the fat pad behind my Achilles at the moment," he said at a Q and A event with supporters in Brisbane. "I've tried joining in a couple of times and it's just not quite right at the moment, but I'm getting there slowly but surely."
Dallas is not expected to play again until 2023. The femoral fracture he suffered against Manchester City needed major surgery and will require a long and patient rehabilitation. The Northern Ireland international is usually an ever-present for the Whites, but he is set to miss a large portion of the 2022/23 campaign.
After picking up an injury in the Whites' 4-0 victory over Blackpool earlier in July, Jesse Marsch admitted that Firpo is set to miss around eight weeks of action.
Firpo looks set to miss the first month of Premier League action, with Leeds' game against Nottingham Forest at Elland Road on September 12 looking like a possible return date.
The 16-year-old suffered a injury during Leeds' 1-0 defeat to Aston Villa, having to be stretchered off after being on the receiving end of a tough challenge from John McGinn. Gray was in obvious pain as he left the field, but Leeds are hopeful that the injury isn't as bad as it first looked, even though McGinn's studs were planted in the youngster's ankle.
“We're hopeful that it's not too bad,” Marsch said. “He was in some pain initially but we're hopeful nothing is broken. Hopefully it's an ankle sprain and we'll see the severity of it in the next couple of days.”