Xavi, who has played in all of Barca's 11 competitive matches this season, was injured on duty with Spain but returned to training on Wednesday and should feature, Barca said on their website.
The European champions have won their opening six matches on four occasions but seven straight wins would be a new best. They top the standings with a perfect 18 points, three ahead of Real Madrid and Sevilla.
Brazilian defender Daniel Alves said Pep Guardiola's side would be relieved if Valencia's injured striker David Villa, who has already netted six times this term, did not recover in time for the match at the Mestalla.
"Villa is the one who calls the shots in attack and their main goal scorer," Alves told a news conference on Wednesday.
"If he doesn't play, it will be welcome news for us as he would be a notable absence," he added. "The match at the Mestalla is always one of the most difficult of the season."
Ronaldo is out for up to four weeks after he aggravated an ankle sprain playing for Portugal on Saturday and will miss Real's match against Real Valladolid, also on Saturday.
Real coach Manuel Pellegrini needs a convincing win after the 2-1 defeat in Sevilla and questions have been asked about the side's dependence on Ronaldo, who has scored five league goals this season.
"Cristiano is a star but we are Real Madrid," Dutch midfielder Royston Drenthe told Marca on Thursday.
"Real Madrid is not just Cristiano Ronaldo, nor Kaka nor Royston Drenthe nor Raul ... we are a team," he added. "And we also know how to win matches without Cristiano."
"We have all that we need to be up there but we have to play with confidence," he told the club's website.
"Our advantage is our experience and we have to exploit that because we have the
