Real Madrid defender Marcelo was left off the squad list for Thursday's match against Granada due to an argument with manager Zinedine Zidane, Goal can confirm.
With Ferland Mendy out for the remainder of the season, Marcelo appeared to be in line to start the crucial match at the Nuevo Estadio de Los Carmenes.
Instead, the Brazilian, who turned 33 on Wednesday, saw himself axed entirely when Madrid announced their matchday squad on Wednesday.
- Phil Jones: Can Man Utd's footballing punching bag ever rebuild his career?
- Santiago Munoz: Newcastle's new teenage signing out to write his own scripts
- Is Chelsea boss Tuchel the best in-game coach in world football?
- 'Grealish is made for the big stage' - Man City star needs to justify £100m pricetag as Guardiola prepares to run the gauntlet
What was the argument about?
Marcelo has been growing increasingly frustrated at Zidane's tactics and line-up decisions as the season has gone on, and that issue came to a head at Tuesday's training session.
The veteran left-back is only 15th in Madrid's squad in total minutes this term as he has been bypassed by Mendy on the team's depth chart.
Marcelo is not the only veteran frustrated with Zidane, with several other established players understood to have grown tired of the Frenchman's methods.
Last week, Goal reported that the consensus in the Madrid dressing room is that Zidane will not be in charge of the club next season, with the Frenchman ready to walk away from the final year of his contract.
Who will replace Marcelo?
With Mendy and now Marcelo out of Madrid's squad, Zidane appears set to give academy product Miguel Gutierrez a chance to start in a big spot.
The 19-year-old has made just three senior appearances for the Blancos this term – all of which have come off the bench in recent weeks.
The state of play in La Liga
Atletico are in pole position to win their first title since 2013-14 as they sit one point clear of second-placed Barcelona having played a game less.
However, Real are only a point further back in third after the same number of matches as their city rivals, and will move into first if they beat Granada and Diego Simeone's side drop points against Real Sociedad on Wednesday night.