Dummett started the Premier League clash against the Foxes at the King Power Stadium at left-back, but he had to play more centrally following the sending-off of Michael Williamson just past the hour mark.
Former Newcastle defender Pearce was following the match - which John Carver’s side lost 3-0 - and he was far from impressed with the shift put in by the 23-year-old.
"I thought he was an average full-back, but as a centre-half… wow, he's been awful,” the former Manchester City and Nottingham Forest manager told BBC 5 live Sport.
Like the rest of the Newcastle players on Saturday, Wales international Dummett had a poor game.
The defender had a pass accuracy of 64%, put in two crosses, won just 33% of the tackles and 17% of the headers he attempted, and made one interception, seven clearances and five blocks.
Over the course of the season, Dummett has featured in 22 Premier League matches for Newcastle.
The Welshman has created 13 chances, has a pass accuracy of 74%, and has won 77 out of 121 headers and 27 out of 49 tackles.