"Now I have to prove who I really am as a man, as a person, and as a footballer," the Portugal international told a news conference. Midfielder Xabi Alonso is back in training with the rest of the group after injury and could feature.
Barcelona coach Pep Guardiola has included Zlatan Ibrahimovic in the squad for the champions' trip to Malaga on Saturday despite the Sweden striker's minor sprained ankle suffered at Racing Santander on Tuesday.
"He has trained well and it's looking better," Guardiola told a news conference. "Let's see tomorrow how he is."
Guardiola said it showed a lack of respect to the other clubs in La Liga to say after four matches that Barca and Real Madrid were the only sides capable of winning the title.
"I don't believe that is the case," he said. "If we have won up to now it's because we have got our act together."
Dmytro Chygrynskiy is set to return to the centre of Barca's defence as the Ukrainian is ineligible for Tuesday's Champions League clash with Dynamo Kiev. Gerard Pique and Seydou Keita could be rested.
Third-placed Sevilla visit fourth-placed Athletic Bilbao on Saturday, with the Andalucians fancying their chances of challenging the leaders after three straight wins.
"If anyone is capable of fighting with Real and Barca for the title it is us," Sevilla president Jose Maria del Nido told sports daily AS. "On our day, Sevilla are as good as Madrid and just a rung below Barca."
Atletico Madrid are away to Valencia, direct rivals for the European places, on Saturday, with visiting coach Abel Resino in the spotlight as his side, placed 19th, seek their first win of the campaign.
"I am going to carry on working to try to turn the situation around," Resino said at a news conference. "One win would lift the spirits and confidence of the players."
France midfielder Robert Pires has called for calm at Villarreal with his side still looking for their first win, away to Deportivo Coruna on Sunday.
"We play good football but just lack a little confidence. No one thought we would be so low in the table (18th) after four matches and now is when he have to prove our worth," he told the club website.
Promoted Xerez, bottom of the league, travel to face Espanyol on Sunday in search of their first top-flight goal.
"We need to put it out of our minds that we are the team everyone thinks they are going to beat," midfielder Momo told a news conference. "Four defeats from four and no goals scored. We are concerned but we aren't anxious."
