Sunderland were beaten 2-0 by the Foxes in their latest outing, with Jamie Vardy scoring twice in the second half to secure the three points.
The Black Cats’ performance was widely considered an encouraging one - as they were able to match Leicester for much of the contest.
However, Vardy felt that Allardyce’s system was too defensive, with Sunderland playing too many central midfielders and leaving Jermain Defoe isolated.
“The Black Cats offered nothing going forward,” he said.
“They lined up with a central midfield threesome of Jan Kirchhoff, Yann M'Vila and Lee Cattermole - all primarily destroyers, rather than creators - so it was no surprise that they didn't cause Leicester's defence too many problems.
“Also, packing the middle of the park doesn't quite work against Leicester, who break so quickly and directly that they almost bypass the midfield when they counter-attack, as was shown in Jamie Vardy's first goal.
“Meanwhile, up front Jermain Defoe was working off scraps and getting involved in physical battles with Wes Morgan, which completely nullifies his strengths as a finisher. The balance of the Sunderland team was all wrong.”
Sunderland had just one shot on target against Leicester, but they did create plenty of chances.
Defoe, Younes Kaboul and Jack Rodwell all missed opportunities to score, and they were made to pay.
The defeat was Sunderland’s second loss in their last eight matches, but their inability to turn draws into victories has been harmful.
Allardyce’s side have failed to move away from trouble despite some improved performances, and they now sit four points adrift of safety.
Sunderland’s next match comes against 17th placed Norwich City at Carrow Road.