Messi (suffering from thigh injury) and Ibrahimovic (hamstring) trained on Friday, and Barca said in a statement that they are ""recuperating well"." Without them, Barca did just fine against Inter, winning, 2-0, in one of its best performances of the season.
"It was an important game and it has given us confidence and lifted morale because we were at our best," Barcelona captain Carles Puyol said. "We could have gone out of the Champions League."
A Messi-Ronaldo duel would pit last year's winner of the two major player of the year awards, Ronaldo, against this year's favorite, Messi. The Golden Ball will be revealed on Tuesday.
Ronaldo came on late in Real Madrid's 1-0 win over FC Zurich in the Champions League. Sunday's game will be the first that Ronaldo and other new Galacticos, Kaka, Xabi Alonso and Karim Benzema, have played against Barca.
"It's difficult to play against them but we also have our own weapons and we're going to do things well so that we can get the win," Ronaldo said. "We want to win in the Camp Nou, and we're going to do things well to give ourselves a chance at victory."