Liam Cooper could make a surprise return to contention for Leeds United ahead of their Yorkshire derby with Sheffield Wednesday.
The Whites captain picked up a groin problem against West Brom on October 1 and it was feared he could miss six weeks of action.
But he and midfielder Jamie Shackleton have returned to fitness this week according to Bielsa.
The head coach also revealed that Pablo Hernandez is making progress and Adam Forshaw will be out for a while yet with a hip problem.
Hernandez was making his comeback from a calf issue in last week’s Under-23s game against Birmingham but suffered a hamstring injury.
“Shackleton and Cooper they are well,” said Bielsa. “Pablo is improving – he is close to coming back to us.”
The news on Forshaw is not so straight forward.
A hip problem originally kept him out of September games against Barnsley and Derby before he returned at Charlton.
But that was the last time he appeared for United, meaning right-back Stuart Dallas has had to fill in at central midfield.
“It’s an injury that is not easy to heal,” said Bielsa.
“It’s not easy to give the prognosis of this injury. For this reason we don’t have a clear reference. The evolution of his process is not linear.
“This kind of injury you have highs and lows until you heal in a definitive way.”
The only positive Bielsa could give on his midfielder was that every effort, both on the player’s behalf and the club’s medical team, is being made to return him to full fitness.
“What we have, Adam is a great professional. He is working hard to try to get out of this situation.
“The same as all the medical staff. They go with him, they help him and they are involved to try to improve the situation as soon as possible.”
Quique Sanchez Flores has confirmed Watford forward Danny Welbeck will be absent for a lengthy period of time after suffering a hamstring injury.
The former Arsenal striker had to be replaced after only four minutes of Saturday’s 1-1 draw at Tottenham in the Premier League. The 28-year-old is likely to be unavailable for “months” starting with this weekend’s home match with Bournemouth.