Daniel Farke revealed a midfield injury boost at his pre-Bristol City press conference on Friday.
January's Player of the Month Mario Vrancic was expected to be out for three weeks after sustaining an ankle ligament injury in the East Anglian derby win over Ipswich Town.
However, Vrancic is ahead of schedule in his recovery and Farke revealed the Bosnian playmaker could return to action on Saturday.
"Mario Vrancic already took part in part of team training on Wednesday," he said. "He is back in contention for tomorrow. He has only been out for 12 days and looked sharp this week. I will make a late decision on him.
There was more positive news delivered on Timm Klose, Moritz Leitner and Alex Tettey.
"Timm Klose had a proper week of training. Moritz Leitner has played just one game in three-and-a-half months but it’s been a good week for them.
"He [Moritz] could start. He’s had three-and-a-half months out and we have to consider that. He’s been out for a long time so we have to be careful.
"My other midfielders have been there with good performances in recent weeks so there’s not too much need to force him back now. But he could start.
"Alex Tettey is back on the training pitch. He's been doing lots of running on his own so could join us for team training on Sunday or the beginning of next week. He should be available for Millwall."
Farke also revealed that Marco Stiepermann was an injury scare at the beginning of the week, but the good work of his medical department has enabled a swift recovery.
"It's been important to have a relaxed week and some days to calm the load. The week has been good but Marco Stiepermann was doubtful at the start.
"He had a small scan on a muscle tear after Bolton because he was a doubt for that game. Therefore, we calmed his load down.
"He has trained with us over the last few days and is contention for tomorrow. Big compliments for my physios to get him ready. Perhaps he’s not 100% for 90 minutes on Saturday but he should play. It’s not like a big muscle fibre crack. The doctors and physios are fine with it and it seems everything is okay."
January signing Philip Heise is yet to feature in a City squad since joining but Farke said he has been impressed with how his new recruit has settled in.
"I'm pleased with Philip. He has needed time to adapt with the guys. He's in a different country and had to learn a different language so it’s never easy.
"He’s done it in a perfect way. The trip to Preston was crucial for him because he had time to speak a lot with the lads. I was pleased with how he’s trained and I’m happy that we have him."