Boro manager Tony Mowbray revealed the 23-year-old, who is out of contract in the summer, was left out of Saturday's FA Cup defeat by Burton because he is in talks over a move, with Bolton believed to be his destination.
"Things are happening," said Mowbray. "It wasn't about avoiding him being cup-tied, he wasn't available due to things that might be happening behind the scenes.
"Having said that, if another club wants to buy him lots of things have to be agreed first with the player and the two clubs, so he may yet be playing for us next Saturday.
"It might become more evident over the next few days. There are things afoot, which is why he din't play. I said I'd pick the strongest team available and David wasn't available."