Diego Costa Talks Bib Incident, Atletico Madrid Transfer Rumours, Jose Mourinho

Chelsea striker Diego Costa has admitted that throwing a training bib at manager Jose Mourinho was a "mistake," but he has not quashed rumours of a potential return to Atletico Madrid.

After not getting off the bench during the Blues' Nov. 29 clash with Tottenham Hotspur, Costa took off his training bib and threw it in the general direction of Mourinho, per BT Sport Football:

The petulant act was widely seen as indicative of the fraying relationship between the out-of-form Spanish striker and his manager, with some reports indicating his Chelsea future was in doubt, per the Express' Tony Banks.

Following the Blues' 2-0 Champions League win over Porto on Wednesday, Costa has now conceded he was wrong to throw his bib, per Spanish radio station Onda Cero (via Simon Johnson in the Evening Standard):

"

The bib [incident] is in the past. I made a mistake, but my relationship with Mourinho is amazing, we get on really well. There are things you need to control, but the bib thing was an impulse. 

I have to improve a bit. The start of the season has not been good for me—not in how I have played nor in goals.

The truth is Chelsea haven’t been in a great moment, above all losing the other day at home (against Bournemouth). It was important to win (against Porto) to make the fans happy and to recover our confidence.

"

He has not, though, dispelled rumours of a potential return to Atleti, pointing to the recent example of Filipe Luis, who moved back to the Vicente Calderon in the summer after just a season at Stamford Bridge, per Onda Cero (h/t Goal.com's Sam Marsden):

"You never know," said Costa. "Look where Filipe Luis is now."

Costa moved to Chelsea from Atleti for £32 million in July 2014, and he netted 20 Premier League goals in his debut season to help the Blues ease to the title, per WhoScored.com.

However, things have not been so rosy in his second season. He has scored only three league goals and Mourinho's men currently sit 14th in the English top flight with little to no chance of finishing the season in the top four, per Bleacher Report's Sam Tighe:

Costa has been widely criticised for his antics on and off the pitch, and also for his misplaced aggression, which was touted last season as a key aspect of his game, per the Telegraph's Paul Hayward:

His contrition will surely be well received by Mourinho, though, and he performed well against Porto in his first start in three matches.

The likelihood is that, if Costa can find some form, not only will rumours of his departure go away, but Chelsea may also start to move up the Premier League table.