Real Sociedad have opened a disciplinary case to investigate the absence of Mexico international Carlos Vela from Monday's training, the club told Diario Vasco on Wednesday.

The club announced they would give Vela time to present his case. Spanish media reports say Vela skipped training to attend a Chris Brown concert in Madrid after photos of the striker appeared on social media. Vela reportedly told the club he had a bout of gastroenteritis.

#VelaDeFiesta ¡Ni cómo defenderte! Carlos Vela no entrenó con la Real Sociedad por irse al concierto de @chrisbrown pic.twitter.com/kSADcZwpED - juanfutbol (@juanfutbol) March 7, 2016

The 27-year-old is considering calling a news conference, the report said, adding that the club could potentially fine the former Arsenal player. According to club sources, Vela has admitted his mistake and has apologised to his teammates and the coaching staff. He did not train with the team on Wednesday, the report said.

Habla Xabi Prieto, capitán de la #RealSociedad. Da la cara tras el incidente de Carlos Vela. pic.twitter.com/KswML7mjmb - SER Dept Gipuzkoa (@SerDeportivosGI) March 9, 2016

Vela teammate Xabi Prieto addressed the subject during a Wednesday news conference ahead of their match against Celta Vigo this weekend, saying that Vela has been "repentant" and confirming that the Mexico international did not train with the team.

X.Prieto: "Carlos Vela está dolido y ha mostrado su arrepentimiento" #RealSociedad - Real Sociedad Fútbol (@RealSociedad) March 9, 2016

At 27, Vela is more than 10 years removed from the golden boy who led Mexico to the FIFA under-17 World Cup in 2005. Unlike players whose international careers are challenged by injuries, Vela's has been marked by disciplinary action. His intemperate quarrel with the Mexican federation was based partly on a reaction to punishment meted out after he was judged to have been partying following a friendly in 2010. The saga cost Vela a spot on the 2014 World Cup squad.

He is struggling thus far with his worst season ever since going on loan to the Spanish club in 2012 after seven years with Arsenal and has scored just four goals in 27 games.