Real Madrid could be sued if Xabi Alonso picks one player vs Osasuna in La Liga opener

Real Madrid could face a legal battle if Xabi Alonso picks one player against Osasuna in their La Liga opener.

Real open their league campaign on Tuesday as they host Osasuna.

It will be Alonso's first game in charge of a La Liga fixture, having replaced Carlo Ancelotti's before this summer's Club World Cup.

The 43-year-old, who enjoyed five seasons at the Bernabeu during his playing career, has been tasked with winning the league title, having won it as a player.

He has been backed by the club in the transfer window, with Trent Alexander-Arnold, Dean Huijsen and Alvaro Carreras coming through the doors.

Not to mention attacking midfielder Franco Mastantuono, who joined the club in a transfer worth £38.5 million and broke an unwritten rule during his official unveiling.

And Mastantuono could play a part in his side's first league game of the season.

Franco Mastantuono has trained with the Real Madrid first-team ahead of potentially making his debut against Osasuna. Image: Getty

But an appearance at the El Sadar Stadium could trigger legal action.

According to Miguel Galan on El Chiringuito, Mastantuono's participation may be in jeopardy due to questions over registration rules.

Per the report, the 18-year-old is officially listed with Real Madrid Castilla, the club's B team, in an attempt to work around regulations on player registration for the first-team.

Osasuna, who filed a complaint against Barcelona last season over Inigo Martinez, could take similar action against Real, accusing them of acting in 'bad faith' by registering him through alternative channels.

If Osasuna decide to act against Real, then they would have 24 hours after tonight's game to file a complaint.

What has Xabi Alonso said about Franco Mastantuono playing against Osasuna?

Mastantuono has yet to feature for Real since his switch from River Plate this summer.

But he could make his debut against Osasuna, with Alonso claiming he could 'get minutes' in their La Liga opener.

Franco Mastantuono during a Real Madrid training session. Image: Getty

Speaking in Monday's pre-match press conference, Alonso revealed: "Yes, he could get minutes tomorrow."

On the Argentine's qualities, the Los Blancos boss added: "He’s going to bring quality, energy. He’s committed defensively, he’s got good drive. In a short time I’ve seen that grit, that Argentine warrior spirit, but also real quality... he’s combative. And he’s got a spectacular left foot."

He also explained where Mastantuono could make an impact.

"Whether on set pieces, the final pass, or finishing, he’s very sharp," he said. "He’s young, but very mature for his age. We need to support him, but he’s already at a very high level."