The Blaugrana won the first leg 4-1 and will look to complete the job at the Stadio Olimpico on Tuesday.
Busquets returned from a broken toe in the first leg at Camp Nou, but re-aggravated the injury and was forced to miss Saturday's league match against Leganes.
Messi scored a hat-trick against Leganes, and there was speculation the Argentine star could start from the bench at Roma after only recently returning from a hamstring injury.
For Roma, Radja Nainggolan returns after missing the first leg through injury while Cengiz Under is only fit enough for a place on the bench.
Barcelona XI: Ter Stegen; Semedo, Pique, Umtiti, Alba; Busquets, Rakitic, Iniesta, Roberto; Messi, Suarez
Subs: Cillessen, D. Suarez, Dembele, Paulinho, Alcacer, Andre Gomes, Vermaelen
Roma XI: Alisson; Fazio, Manolas, Jesus; Kolarov, Strootman, De Rossi, Nainggolan, Florenzi; Schick, Dzeko
Subs: Skorupski, Peres, Pellegrini, Gerson, Gonalons, Under, El Shaarawy