Barcelona have a crisis at left back ahead of the first leg of their Champions League semi-final against Real Madrid following the news that Maxwell has not made the squad.
The Catalans, who last week lost the Copa del Rey final to their great rivals, had already lost Brazilian full-back Adriano for most of the season with a muscular problem.
Now his compatriot Maxwell has also fallen victim to injury and has been omitted from Barca's squad following a groin problem picked up in a victory over Osasuna at the weekend.
Both players have performed in defence at times this season, and if they do drop into the back four then Carles Puyol could move across to combat Ronaldo at left back.
The captain has been joined in the squad by fellow centre-back Gabriel Milito, who has shaken off an injury to declare himself fit for the Champions League Clasico.