The English international shocked Sunderland fans when he moved to Aston Villa in January after playing for the club for only 16 months.
The ex-Ipswich player will make his first return to the Stadium of Light when Villa take on the Mackems in Saturday's Premier League clash.
Bruce knows that the 27-year-old is an amazing striker and he admits that he did not want him to leave but he would rather focus on his opposition than a single player's return. "For me, Darren did fantastically well and no-one can deny that." said Bruce.
"His goal-scoring record here was quite staggering and I think you could argue that the goals he gave Aston Villa when he left us last season probably kept them up.
"He could have been, in my opinion, one of the greats of Sunderland, and I'm talking about up there with the very best goal-scorers in the club's history, if he had hung around. He would have broken a lot of records.
"But that didn't happen and it's gone now, it's finished, its history and we all have to move on. As far as I'm concerned, the over-riding thing is to focus on Aston Villa and not get side-tracked by the sideshow of Darren Bent's return to the club."