Despite training and travelling with the Trotters' first team on many occasions during his seven weeks in Lancashire, Brattan – who joined Premier League giant City on a four-year deal at the end of October as a free agent – has yet to be named in a first team squad by coach Neil Lennon.
It’s understood Brattan, 25, has looked sharp and lively in training for the Championship's bottom club and will use the experience as a springboard to another loan spell as his City bosses seek to acclimatise him to the demands of the English game after six seasons in the A-League with Brisbane Roar.
Bolton have drawn four and lost four since Brattan's arrival, with Lennon saying last month: “City contacted us and then we did some homework on him.
“It was an offer of a player to get some experience for him and to help City out. It’s good to have a relationship with Man City – I know some people there.
“Watching him in training, he can handle the ball. He just needs to work on his physicality – obviously his fitness levels are down compared to the rest.
“It is not costing the club a penny, so it’s a no-brainer. But he will need to get accustomed to the pace of English football compared to the A-League.”
With Brattan's loan spell to expire on 3 January, he has four games left after the 2-2 draw at Charlton Athletic to catch Lennon’s eye and land a promotion to the top squad.
Brattan, who has featured in several games for the Trotters' U-21s, could not have come at a tougher time for the once proud club.
To heap on the hurt, there is also a winding up order pending from Britain’s Revenue and Customs over $1.2 million of unpaid taxes as the club drowns in $248 million of debt.
Bolton are marooned six points from safety with just one win in 21 games.
Bolton players went unpaid in November, though with Brattan’s wages guaranteed by the cashed-up City Football Group, he will not have been affected.
Those that were can, under Football League rules, terminate their contracts with two weeks' notice should the same happen this month.
The Trotters would be deducted 12 points were they to go into administration, all but guaranteeing relegation.