The two-week Christmas break and the January transfer window offer teams a good chance to take a step back, reassess their objectives for the season and even, if the price is right, improve their squad.

It’s difficult to find value in the January transfer market but there are always a handful of deals that end up changing a team’s fortunes in the second half of the season and beyond.

Marcelo, for example, joined Real Madrid during the cold months of January back in 2007. It is highly unlikely, practically impossible even, that any of the players on this list will go on to win over 20 trophies in total during a glittering 15-year stay in Spain. But who’s to say?

We stress these are January arrivals because some of the players mentioned were promoted from the clubs’ reserve sides or arrived on short-term loan deals. Either way, they have made an impact and we think they might continue to do so even if it is for just a whirlwind spell until the end of the season.

Pau Cubarsí – Barcelona

Xavi Hernández is leaving Barcelona at the end of the season. The story of his time as the manager of the club isn’t finished yet and we’ll have to wait to see how history views his tenure at the club. But one thing he should get credit for is bringing several young players into the first team.

Three of the six youngest players to play across Europe’s top five leagues this season are from Barcelona — Lamine Yamal, Pau Cubarsí and Héctor Fort. They’re not just young in footballing terms, they still have a few years left as teenagers. Both Yamal and Cubarsí were 16 when given their debuts.

Yamal has garnered praise from all over since his emergence but Cubarsí has been no less exceptional. He is 17 now but plays like an old hand.

Xavi says Cubarsí is Barcelona’s best option to bring the ball out from the back and has placed huge responsibility at the feet of the teenager. He took up the central position in a back three against high-pressing Getafe last weekend, orchestrating Barça’s build-up with poise.

Cubarsí balances risk with reward and maintains a very high pass completion rate in the process. In total, he has completed 505 of his 554 pass attempts (91% accuracy) this season.

But he isn’t a play-it-safe-sideways-pass merchant. Mika Mármol (187) from Las Palmas is the only defender with more forward passes than Cubarsí (176) since the teenager’s debut.

Barcelona looked to their past in the hiring of Xavi but during his spell in charge, he has given us a glimpse into the future.

Johnny Cardoso – Real Betis

Real Betis, like several La Liga teams, are currently tasked with reducing their wage bill to keep within the spending limits imposed on them by the league all the while remaining competitive. They’ve had to sell players like Sergio Canales, Luiz Felipe and Luiz Henrique. They snapped Bayer Leverkusen’s hand off when the German side came looking to sign Borja Iglesias in January. It’s a team that has lost several important pieces out of financial necessity.

The key to maintaining this balance is smart recruitment. Johnny Cardoso, the 22-year-old American defensive midfielder looks like one of the smartest moves of the season. Since making his debut after arriving from Internacional in Brazil, no outfield player has played more minutes for Betis (703).

Since his debut on 21 January, Beñat Prados (5.8) is the only La Liga player averaging more tackles and interceptions combined per 90 across all competitions than Cardoso (5.6).

The most telling sign that Betis are planning for the future with Cardoso is how they have handled Guido Rodríguez’s contract negotiations. The 29-year-old Argentine was seen as vital to Real Betis in midfield but since Cardoso emerged as a veritable baller, the contract offer on the table has expired and it looks like he will leave in the summer.

Isaac Romero – Sevilla

Sevilla are in the process of rejuvenating their squad. Ivan Rakitic, Papu Gómez and Fernando have left and they are likely in for a big churn this summer too.

Isaac Romero was seen as a cheap, viable option in January but has turned into something more. He’s 23 now and was promoted from Sevilla’s second team having never truly made an impact at that level to the point where he was considered good enough to play for the first team.

As they plan their squad for the future, they can take solace in the fact that Romero has settled into life as a first-teamer with unusual ease.

He has the most big chances created (5) in La Liga since his debut on 12 January. He has also scored three goals in seven La Liga games (no penalties) so far and might have had another against Real Madrid if it weren’t for a save of the season contender from Andriy Lunin.

Out of necessity, he was given a chance and he has been a bright spot on another wise lustreless season for Sevilla. No player has been involved in more open-play attacking sequences than Romero since his debut (19).

It’s unusual that any player arriving in January would assume such a prominent role and even less so for a 23-year-old reserve player who hadn’t made the grade before now.

Luka Romero – Almería

It’s another Romero, except this one has come with some hype.

The Opta supercomputer predictions give Almería the most slender of chances of staying in the top flight this season. They haven’t won a game yet in the league and the outlook is not good, but their performances haven’t been as bad as their historically poor record of nine points from 26 games suggests.

Almería have been competitive against each of the top five teams in the league, losing 3-2 to both Barcelona and Real Madrid with the two giants needing late goals to win the game. They have also drawn with Girona and Athletic Club this season along with, most recently, Atlético Madrid. The game ended 2-2 with a brace from teenager Luka Romero, who arrived on loan from Milan in January.

It’s early days but Romero, who became the youngest player to ever play in La Liga when he debuted for Mallorca back in 2020 as a 15-year-old, might find an environment where he can finally come good on his potential. Jonathan Viera, another January signing, found Romero for his second against Atlético. The former Las Palmas playmaker and Romero could become a force as Almería try to save face for the rest of the season.

Romero is only 19 years old despite being a four-year professional and having spent time at Serie A sides Milan and Lazio. He’s on loan for the rest of the season and Almería have almost no chance of surviving relegation, but the young Argentine might give the fans reason to celebrate before the season is over.

Romero might also be the key to ensuring Almería don’t end the season as the worst team to ever play in La Liga according to the record books.

Yerson Mosquera – Villarreal

Villarreal have been better defensively recently. They’re better, well, because they had to improve. The squad is too good to even be mentioned in relegation chatter, which is exactly where they found themselves midway through the season. They have already been through two managers after sacking Quique Setién and Pacheta.

Marcelino is the third man man in the dugout in 2023-24 after his ill-fated spell at Marseille. And he has spoken ad nauseam about the team’s need to improve defensively. They signed Eric Bailly and Yerson Mosquera in January to sure up a leaky backline.

Mosquera has played four times, an admittedly small sample, but since his arrival Villarreal are unbeaten in those games (two wins, two draws). Their goals conceded per game has dropped from 1.9 to 1.5 with him on the field. One of Villarreal’s problems was their inability to defend against counters. They have conceded 45 shots from high turnovers, which is behind only Girona (48) and Atlético Madrid (46) this season in La Liga.

To combat that problem, Marcelino has preferred more athletic players with Dani Parejo dropping out of midfield for Santi Comesaña even since returning from injury and Mosquera featuring at centre-back but also as a right back, most recently, during Villarreal’s 3-1 victory over Real Sociedad. It’s just a loan deal but if Mosquera continues his good start to life in Spain, they might test the waters on a permanent deal for the 22-year-old who hasn’t found a place at Wolves.

Gonçalo Guedes is worth a mention too. He also arrived from Wolves and scored and assisted in a win over Barcelona back in January. It was just his second game for the Yellow Submarine and he will likely catapult Villarreal back into the top half if he continues with his current form. They are currently 13th on 29 points.

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