Jamie Elliott could return next week, Craig McRae has revealed in his mid-week presser on Wednesday.
"It was his first main session (today) so it's a massive step forward for him," Fly said.
"Next week we hope he will be able to put his name up."
Jack Ginnivan and Beau McCreery did not train on Wednesday - they are both resting at home with the same cold symptoms as a small number of players in the last fortnight.
"They are both sick - it has gone through the place three weeks in a row and it's unfortunate, but we will manage those guys right up until game time," Fly said.
"We are hopeful 24 hours will make a big difference and they will be able to get up.
"Attention to detail is something we spoke about during the week - if you have a runny nose or a cough you can still do these things for the team.
"We don't want to make excuses but we have had a couple of guys who have been disrupted."
Marcus Bontempelli and Alex Keath are both likely to return for the 10th placed Bulldogs.
"They have had an up and down season and we know their best is really dangerous," Fly said.
"Our pressure last week around the ball was our worst for the year.
"We played some good footy but we also had a few lapses and we want to make sure we don't have those lapses on Friday night.
"We want to win every week and we are preparing to win every week, but we also have an eye on the future."