Diego Costa is reportedly refusing to train for Atletico Madrid after the club opened up disciplinary proceedings against the striker.

Costa was handed an eight-game ban for his actions towards the referee in Atletico Madrid's defeat to Barcelona earlier this month - four for abusive language and four more for grabbing the official's arm.

It means that the Brazil-born forward's season is over, with his red card in the 0-2 defeat at the Nou Camp also ending Atleti's chase of Barca and their title hopes.

Atletico responded by opening disciplinary proceedings against Costa, owing to the severity of his offences, and the striker has refused to train according to local newspaper AS.

Late goals from Luis Suarez and Lionel Messi almost certainly handed the defending champions a fourth title in five years despite the best efforts of Diego Simeone's side.

Ranked and rated: Champions League contenders Show all 9 1 / 9 Ranked and rated: Champions League contenders Ranked and rated: Champions League contenders Ranked and rated: Champions League contenders epa06160739 View of the UEFA Champions League trophy during the UEFA Champions League 2017/18 draw, at Grimaldi Forum, in Monaco, 24 August 2017. EPA/SEBASTIEN NOGIER SEBASTIEN NOGIER EPA Ranked and rated: Champions League contenders Spurs triumph in classic Tottenham edged an instant classic against Manchester City, who were the favourites entering the final eight. They lost 4-3 in the second leg but triumphed on away goals after trailing in the tie with 30 minutes remaining. City joined Borussia Dortmund as scalps in an impressive run to the semi-finals REUTERS Ranked and rated: Champions League contenders 4. Tottenham Hotspur Champions League grade: A- Odds: 4/1 Getty Images Ranked and rated: Champions League contenders The dream run continues This super talented team marches on after repeating their last 16 shock over Real Madrid to eliminate Cristiano Ronaldo and Juventus. A collection of supremely talented young players with experience sprinkled in, nothing fazes this side Getty Ranked and rated: Champions League contenders 3. Ajax Champions League grade: A+ Odds: 4/1 Getty Images Ranked and rated: Champions League contenders Liverpool return to last four The Reds have eliminated Bayern Munich and Porto to arrive at this stage as perhaps the most complete side. With a different identity to last season's chaotic approach, Jurgen Klopp's side now have greater control, but who can truly control Lionel Messi? AFP/Getty Images Ranked and rated: Champions League contenders 2. Liverpool Champions League grade: B+ Odds: 5/2 Bongarts/Getty Images Ranked and rated: Champions League contenders Messi still on top Still capable of hitting heights no player in world football can, Lionel Messi is inspiring Ernesto Valverde's side, with Lyon and Manchester United dispatched so far. Philippe Coutinho is now brimming with confidence after a difficult season, while Luis Suarez remains one of the most deadly strikers in the game, they continue to look fragile at the back and lack the usual vice-like grip of control their midfield once gave them, but Messi still makes them the team to beat Getty Images Ranked and rated: Champions League contenders 1. Barcelona Champions League grade: B+ Odds: 6/4 REUTERS

The goals came with Atleti down to 10 men following Costa's first-half dismissal for comments made to referee Gil Manzano.

Manzano's post-match report said: “In the 28th minute, number 19… Diego Costa was sent off for the following reason: saying to me loudly, in the following terms: ‘I s**t on your w**** mother, I s**t on your w**** mother!’”

The Spanish authorities have now taken action handing the Spanish international a four-game suspension for the comments and a further four-game sanction for grabbing the referee's arm.

Costa has also been fined €6000. Atletico have the power to appeal against the decision.

Teammate Koke revealed that Costa had apologised to rest of his team and had insisted he had not insulted the referee and that comments were aimed at himself.

“Something always happens to us when we come here,” added Koke. "In the last 11 games, I think there have been seven red cards and not all of them have been fair.

Diego Costa confronts the referee after his red card ( EPA )

"We must try to stay as high as possible in LaLiga. We will have to watch what happened [against Barcelona].