The Bolton News says sources in the Midlands claim Villa are close to sealing a deal for Portsmouth's Sylvain Distin - which will give incentive to the Whites to mount their bid.
Gary Megson wants another experienced central defender in his ranks, having juggled Andy O'Brien, Danny Shittu and ex-loanee Sebastien Puygrenier alongside regular Gary Cahill last season.
And he wants to recruit the man whose arrival at Villa Park convinced Cahill to quit the Midlands for Bolton in January 2008.
Knight is also a close friend of new signing Sean Davis.