A crestfallen Brattan was clearly playing through the pain barrier in Saturday's second-leg 0-0 draw with the Central Coast Mariners, and the agony of another semi-final loss will have only increased his discomfort.
To add to Sydney's woes, there were several questionable calls from referee Alireza Faghani, with the Sky Blues denied two penalties in Gosford.
Sydney also had a goal chalked off as they looked to square the tie, which the Mariners claimed 2-1 to cruise through to a home grand final.
Sydney boss Ufuk Talay was visibly aggrieved with Faghani and midfielder Anthony Caceres was sent off after fulltime for protesting the referee's decisions.
Brattan claimed he usually liked Faghani's laissez-faire approach but was left bewildered by the crucial calls that went against Sydney.
"If it was one decision, you'd be like 'OK', but there were three clear decisions," Brattan said.
"That's what the VAR is there for, you get it wrong on the pitch and you're meant to look at it.
"I saw the Victory handball (in the earlier semi-final) and all we ask for is consistency and we haven't had that at all this season and every team is saying the same thing.
"It's tough to take but I'm extremely proud of these boys, a fantastic group and I'm very proud of them."
Brattan injured himself in Sydney's elimination final win over Macarthur a fortnight ago and has been playing with pain-killing injections.
"My ankle is not good… I've got a couple of fractures and a couple of floating bones," he said.
"I got a jab before the Mariners game last week and I got another jab at halftime.
"We're talking about a clean-out but I'll make that decision later."
Brattan is also unsure whether Saturday's game was his last for Sydney.
The 34-year-old is off contract and has been linked with a move to Macarthur.
"I'm off contract, but I am a Sydney FC player and I love the club and the group of boys," he said.
"I was just fully concentrating on these games, I'll reflect now, speak to my partner and do what's best for me and my family, but I've loved every minute here and if I could stay on I'd like to stay."
