The midfielder has been hampered by injury so far this season but is targeting a comeback sooner rather than later
The midfielder first picked up the problem while on international duty with Germany back in September and there were even fears he would have to undergo an operation in a bid to eradicate the problem.
But a prolonged period of rest has seen the 23-year-old make a gradual recovery and he is hopeful of pulling on the Dortmund jersey sooner rather than later.
He told Bild: "Slowly but surely it is getting better. I've even been doing sprinting and working on my conditioning - there are only a few more percentage points for me to reach.
"Of course I hope that I can return as quickly as possible, but I am not completely pain free yet and so I must continue my treatment."
BVB have felt the full force of his absence, with defender Mats Hummels also ruled out until next year with a broken foot, but Gundogan has made participating at World Cup 2014 his top priority.
"It's quite possible that I can be fully fit after the winter break," he added. "Of course I want to return as quickly as possible and play again for Dortmund, but Brazil of course is top priority."
The former Nuremburg man has featured just once this season - in BVB's 4-0 win away to Augsburg - but made 40 appearances last term as the club finished runners-up to Bayern Munich in the Bundesliga and Champions League.