Hilario is preferred to Ross Turnbull as Petr Cech's replacement.
Nicolas Anelka comes in for Florent Malouda in the team's only other change from the starting 11 at Stoke. John Mikel Obi is again in the team.
West Brom are unchanged from the side that lost to Man United.
Chelsea will line-up in the following 4-3-3 formation:
17 Jose Bosingwa
26 John Terry (c)
3 Ashley Cole
12 John Mikel Obi
8 Frank Lampard
39 Nicolas Anelka
9 Fernando Torres
21 Salomon Kalou
Subs: 22 Ross Turnbull, 2 Branislav Ivanovic,19 Paulo Ferreira, 20 Josh McEachran, 10 Yossi Benayoun, 15 Florent Malouda, 11 Didier Drogba.
West Brom are expected to line up in the following 4-4-2 formation:
Foster; Reid, Tamas, Olsson, Shorey; Brunt (c), Scharner, Mulumbu, Morrison; Tchoyi, Long.
Subs: Fulop, McAuley, Cech, Dorrans, Reyes, Cox, Odemwingie.
The referee is Lee Mason.