Williams, who has twice appeared as a replacement, plays at centre with Peter Betham, while Tommy Bell, Graham Kitchener and Jordan Crane also start.
Saracens make five changes to the side that beat London Irish in the United States last week, with hooker Schalk Brits back from suspension.
Marcelo Bosch and Neil de Kock start in the backs while Alistair Hargreaves and Kelly Brown return to the forward pack.
Leicester Tigers: Bell; Thompstone, Betham, Williams, Goneva; Burns, Kitto; Ayerza, Thacker, Mulipola, Barrow, Kitchener, Fitzgerald, McCaffrey, Crane (capt).
Replacements: Bateman, Genge, Balmain, Croft, Fonua, Harrison, Smith, Veainu.
Saracens: Goode; Ellery, Bosch, Barritt (capt), Wyles; Mordt, de Kock; Barrington, Brits, Figallo, Hamilton, Hargreaves, Rhodes, Brown, Wray.
Replacements: Porecki, Lamositele, Du Plessis, Smith, Fraser, Wigglesworth, Tompkins, Ransom.
Owen Williams makes his first Leicester start since suffering a broken jaw.