The veteran striker came on for the visitors just after half time, yet Villa took the lead through Stephen Warnock after 60 minutes. However, they were soon behind after goals from Martin Petrov and David N'Gog. The result pulls Villa into the relegation battle and McLeish feels that Davies is the reason for the Trotters' comeback.
"Kevin Davies caused them some problems, I thought they were a little bit aggitated by Davies' presence," said McLeish.
"The big fella roughs people up and messes them about and unfortunately caused us to lose concentration for the first goal when Carlos [Cuellar] gave away the penalty.
"We have got to be stronger than that at this level, you have to be stronger as we were penetrated by a Davies flick on and we really can't lose goals as easy as that."
Villa remain 15th after the home defeat but are now just three points clear of safety with three games left to play.