Blues coach David Nucifora has made four changes from the side which beat the Cheetahs 26-8 last weekend as lock Williams and hooker Mealamu drop to the replacements bench.
Greg Rawlinson and Derren Witcombe come into the team, while flanker Angus Macdonald replaces Justin Collins.
Winger Rudi Wulf replaces hamstring victim Anthony Tuitavake, while All Blacks winger Joe Rokocoko keeps his place on the bench.
Blues to play Sharks: Ben Atiga, Doug Howlett, Isaia Toeava, Sam Tuitupou, Rudi Wulf, Isa Nacewa, Steve Devine; Tony Woodcock, Derren Witcombe, John Afoa, Greg Rawlinson, Troy Flavell (captain), Angus Macdonald, Daniel Braid, Jerome Kaino.
Replacements: Keven Mealamu, Nick White, Ali Williams, Justin Collins, David Gibson, David Holwell, Joe Rokocoko.