The Reds trail 3-0 from the first leg and their odds of reaching a second consecutive Champions League final were further dented when Salah suffered concussion in the 3-2 win at Newcastle on Saturday.
Firmino only made a cameo appearance in the first leg due to a groin injury and misses out with Origi and Shaqiri, who combined for the winning goal at Newcastle, given their chance to shine.
Barcelona boss Ernesto Valverde has no such problems as he names the same side that started the first leg, having made 11 changes for the weekend defeat at Celta Vigo with the La Liga title already won.
Lionel Messi captains the Catalans, while former Liverpool favourites Luis Suarez and Philippe Coutinho start on their return to Anfield.
Liverpool (4-3-3)
Alisson Becker; Trent Alexander-Arnold, Joel Matip, Virgil van Dijk, Andy Robertson; James Milner, Fabinho, Jordan Henderson (capt); Xherdan Shaqiri, Divock Origi, Sadio Mane
Coach: Jurgen Klopp (GER)
Barcelona (4-3-3)
Marc-Andre ter Stegen; Sergi Roberto, Gerard Pique, Clement Lenglet, Jordi Alba; Sergio Busquets, Ivan Rakitic, Arturo Vidal; Lionel Messi (capt), Luis Suarez, Philippe Coutinho
Coach: Ernesto Valverde (ESP)
Referee: Cuneyt Cakir (TUR)