The in-demand midfielder will be hoping to lead the Hammers to European glory for the first time in 58 years in what could be his final appearance for the club amid strong interest in his services from a host of top European clubs.
David Moyes has made five changes to the side that lost 2-1 against Leicester City in their final Premier League game of the season last weekend, with cup goalkeeper Alphonse Areola unsurprisingly taking his place between the sticks at the expense of Lukasz Fabianski.
Kurt Zouma replaces Thilo Kehrer in central defence and Emerson Palmieri is preferred at left-back ahead of Aaron Cresswell, while Czechia international Tomas Soucek will partner Rice in the middle of the pitch.
Pablo Fornals - who scored a late winner in the semi-final second-leg win over AZ Alkmaar - is replaced on the right flank by Jarrod Bowen, with Lucas Paqueta and Said Benrahma retaining their places in the final third in behind central striker Michail Antonio.
As for Fiorentina, Vincenzo Italiano has made seven changes to the side that beat Sassuolo 3-1 in their final Serie A game of the season last Friday, and the most notable alternation sees Luka Jovic start as the central striker at the expense of top scorer Arthur Cabral.
Cabral, who is currently leading the way in the race for the ECL Golden Boot with seven goals, will begin tonight's showpiece event as a substitute along with Jonathan Ikone, as Jovic and Nicolas Gonzalez have been selected to start in the front three alongside Christian Kouame.
Moroccan World Cup star Sofyan Amrabat will link arms in midfield with Giacomo Bonaventura and Rolando Mandragora, with the latter two returning to the first XI at the expense of Gaetano Castrovilli and Alfred Duncan.
Nikola Milenkovic and captain Cristiano Biraghi are recalled at centre-back and left-back respectively, while first-choice shot-stopper Pietro Terracciano comes in to replace Michele Cerofolini.
Fiorentina: Terracciano; Dodo, Milenkovic, Ranieri, Biraghi; Bonaventura, Amrabat, Mandragora; Gonzalez, Jovic, Kouame
Subs: Cerofolini, Sapornara, Cabral, Ikone, Terzic, Venuti, Martinez Quarta, Duncan, Bianco, Barak, Brekalo, Igor
West Ham United: Areola; Coufal, Zouma, Aguerd, Emerson; Rice, Soucek; Bowen, Paqueta, Benrahma; Antonio
Subs: Fabianski, Johnson, Cresswell, Fornals, Lanzini, Downes, Cornet, Ings, Ogbonna, Kehrer, Potts, Mubama