Hamilton takes his place on the wing after being rested for last weekend's Guinness Premiership win over Bristol Rugby, while Ayerza comes into the front row, alongside George Chuter and Martin Castrogiovanni.
Craig Newby keeps his place at blindside, with Ben Woods and Jordan Crane completing the back row as Tom Croft and Ben Kay continue at lock. Geordan Murphy again captains the team from full-back.
There are six internationals on the bench, including Julian White, Harry Ellis and Aaron Mauger who makes his return to the matchday squad after injury.
Tickets for Sunday's semi-final will remain on sale at the Millennium Stadium on Saturday and Sunday.
Leicester Tigers (v Cardiff Blues, Millennium Stadium, Sunday 3pm) 15 Geordan Murphy (captain) 14 Scott Hamilton 13 Dan Hipkiss 12 Sam Vesty 11 Johne Murphy 10 Toby Flood 9 Julien Dupuy
1 Marcos Ayerza 2 George Chuter 3 Martin Castrogiovanni 4 Tom Croft 5 Ben Kay 6 Craig Newby 7 Ben Woods 8 Jordan Crane
Replacements 16 Benjamin Kayser 17 Julian White 18 Marco Wentzel 19 Lewis Moody 20 Harry Ellis 21 Aaron Mauger 22 Matt Smith