A ranar 28 ga Nuwamba, 2014, Williams ta sanar da cewa Wolff zai kasance tare da tawagar don kakar 2015 a matsayin mai gwadawa, tare da matsayinta ya fadada don hada da horo biyu na Jumma'a da kuma gwaji biyu. Bayan tuki a cikin gwajin pre-season na Formula One, Wolff ya yi zagaye na 1: 29.708 a farkon zaman horo na
Gasar Grand Prix ta Spain kuma ta dawo cikin matukin jirgi a cikin horo don Babban Prix na Burtaniya, yana buga 1: 37.242 don matsayi na 13 mai daraja daga cikin motoci 20.