The South American pair are set for a shootout today at Anfield.
Pellegrini said: "I think a lot of Suarez, he’s a great player, not only a striker. He scores goals but he also plays a lot for the team.
"But if you tell me I could change him for Sergio, I’d say no. Sergio has had a difficult season with injuries but I am sure that any team who played with him would be improved.
"He is very strong inside the box, scores a lot of goals and can play with the midfielders. He is a big player."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball