The striker, though, has had good news when it comes to his ankle injury after spending time behind the scenes taking part in some light outdoor sessions.
Bruce told the Sunday Sun: "I am never going to put an exact time on it.
"The good thing for the supporters is that there's good work he's done on the training ground with the rehab and physio people.
"The ankle has had no ill effects. He is not sore and not swollen.
"In the past that has been the case."
When asked what the next step for Carroll will be, Bruce said: "Let's hope he can come and train with us for a couple of weeks.
"The early signs are encouraging."