Leaders Real Madrid may recall Marcelo at home to fourth-placed Levante on Sunday after the Brazil full-back, who has been sidelined by a thigh problem, came through a full training session on Friday.
Coach Jose Mourinho had 21 of his 23 squad members available for the session including winger Angel di Maria and midfielder Sami Khedira who are returning from injury.
Only midfielders Lassana Diarra and Hamit Altintop were absent, the club said on their website.
Real will have their lead over second-placed Barca cut to four points by the time they meet Levante at the Bernabeu if the champions win at Osasuna on Saturday.
With 21 matches played, Real have 55 points from a possible 63 with Barca on 48. Valencia, who host struggling Sporting Gijon on Sunday, are a further 11 points back in third.
Barca have Pedro available at Osasuna after he was given the all-clear on Friday following an injury layoff, the world and European champions said on their website.
Pedro's Spain team-mate Sergio Busquets is out after he sustained a deep gash to his leg in last week's 2-1 win at home to Real Sociedad.
"Busquets is not travelling because he is not able to play," coach Pep Guardiola told a news conference. "The wound could open and we would lose him for three weeks."
The match at the Reyno de Navarra stadium in Pamplona is among the toughest left this season and only a win will do, Guardiola said.
"In the league we are at the very limit and the players know it," the former Barca and Spain midfielder added. "Whatever happens though I will not let the players throw in the towel."
Centre-back Gerard Pique also warned Real that Barca would not give up on their bid for a fourth straight domestic crown.
"The struggle for the title is going to be a long one for whoever ends up winning it," the Spain international said. "Count on us being there in the fight at the end of the season."
The latest round of matches have been overshadowed by the prospect of another strike after the professional football league (LFP) broke off talks with the players' union (AFE) over a wide-ranging agreement covering wages and working conditions.
The season started a week late in August after the AFE called a stoppage as part of a bid to help players whose wages had not been paid, especially those at clubs in lower divisions that are suffering from financial difficulties.
A preliminary deal was struck which allowed the season to get underway and the two sides had been discussing a variety of issues before the LFP accused the union on Thursday of "intransigence" and ended negotiations.
Atletico Madrid are playing more like a team and have sorted out some of their problems at the back since the arrival of new coach Diego Simeone at the end of last year, according to Turkey midfielder Arda Turan.
"We have plenty of quality and we are playing better defensively," Turan told a news conference ahead of Saturday's game at Racing Santander. "We feel like a team and we are doing what the coach asks."
Atletico are seventh on 30 points while Santander are mired in the relegation zone on 22.
Athletic Bilbao reached the King's Cup final with an 8-3 aggregate win over Mirandes on Tuesday and victory at Real Betis in Saturday's late kick-off would lift them above Espanyol and Levante into fourth on 33 points, at least for a day.
Espanyol host bottom club Real Zaragoza on Sunday.
