Barcelona and Atletico Madrid resume their quest for the Spanish league title after a two-week winter break.
The teams share the league lead with identical records of 15 wins, one draw and one loss. Real Madrid trails by five points.
Here are five things to know about this weekend's matches:
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WAITING FOR MESSI
When Barcelona hosts Elche on Sunday, most of the eyes at Camp Nou will be looking for Lionel Messi either in the dugout or the stands.
Messi has been at home in Argentina healing a left hamstring he tore on Nov. 10. The club's all-time leading scorer is expected to return to the Catalan capital and train again with his teammates later on Thursday, but the team may not rush him onto the field against promoted Elche considering he has had three muscle injuries this season.
"We know that he is coming back fit," Barcelona midfielder Andres Iniesta said. "We will now see how quickly he picks up training again. It's great news for us as far as his importance to our level of play and the intimidation factor he brings."
Neymar will return for Barcelona after a one-game suspension for accumulation of yellow cards. Goalkeeper Victor Valdes may also rejoin his team after a long injury layoff.
Elche, back in the first division after a 25-year hiatus, has never won at Barcelona in 19 league visits.
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AND FOR BALE
Real Madrid hopes it can get Gareth Bale back for Monday's home match against Celta Vigo.
Bale missed Madrid's final two games of 2013 with a knock on his left leg and has been left off the squad for Thursday's friendly against Paris Saint-Germain in Doha.
Madrid coach Carlo Ancelotti had said that Bale was expected back two weeks ago for its trip to Valencia, but Bale didn't make it in time.
Bale, who joined Madrid for a world record transfer fee, last played in its 2-2 draw at Osasuna on Dec. 14.
Celta is in 16th place, but has more road wins (3) than at home (1).
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COSTA VS. CABALLERO
Diego Costa will aim to add to his league-leading 19 goals this season when Atletico visits Malaga on Saturday.
To do so, he will have to beat Malaga's Willy Caballero, one of the league's best goalkeepers.
Costa has scored five goals in the last four rounds and leads Madrid's Cristiano Ronaldo by one in their scoring duel.
An Atletico win will give the team the provisional lead. Malaga, however, has improved of late and is unbeaten in three rounds and with wins in the last two, relieving some pressure on coach Bernd Schuster.
Atletico coach Diego Simeone has the safest job in Spain after forging the team into a legitimate title contender.
"With our effort, we hope that this year we can continue to make our fans happy to belong to Atletico Madrid," Simeone said.
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BASQUE BATTLE
Real Sociedad hosts Athletic Bilbao on Sunday in a Basque Country derby will both battling for Spain's final Champions League spot.
Bilbao enters in fourth place and with four wins in a five-game unbeaten run. Sociedad has improved after its exit from the Champions League and has only one defeat at Anoeta Stadium in league play this season.
It has only lost once in its last nine league games and has risen into fifth place four points behind Bilbao.
Sociedad is led by French forward Antoine Griezmann and his 11 goals, making him the league's third leading scorer.
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PIZZI DEBUTS
Juan Antonio Pizzi will debut as Valencia coach on Saturday at home against crosstown rival Levante.
Pizzi inherits a Valencia side in 11th place and level on points with Levante — both only five points from the relegation zone — and far from the club's goal of making a top-four finish and returning to the Champions League.
"We have to set ourselves shorter-term goals that are more realistic, while not discarding that final objective," Pizzi said at his presentation.
Pizzi, a former Argentine forward, played for Valencia, Barcelona, Villarreal and Tenerife. He replaces the fired Miroslav Djukic.