Chelsea star Willian has criticised Antonio Conte's decision to force Diego Costa out of the club last year.
The Spain international spent three seasons at Stamford Bridge, winning two Premier League titles before he was ruled surplus to requirements by Conte.
The Italian coach sent the forward a text telling him that he did not need him in the squad, which Costa described as "a moment of madness" before sealing his return to Atletico Madrid last September, even though he was not eligible to play until January this year because of the Spanish side's transfer ban.
And Willian feels the decision was a mistake from Conte, revealing that he had a few issues with the figures in the dressing room.
"He also had problems with David Luiz and Costa," Willian told ESPN. "With Diego, I remember it was after the season. I was in Australia with Brazil and Diego texted me.
"He said: 'I'm leaving, Conte said he doesn't need me anymore'. I said: 'What do you mean?' And he said: 'He texted me saying that he doesn't need me on the team anymore and I'm not supposed to go back'.
"You don't lose a player like Diego Costa. It was a difficult situation."
Costa scored 58 goals in 120 appearances for the English side before returning to the Rojiblancos, where he had previously won La Liga and the Europa League, and reached the Champions League final in a successful four-year spell.
Willian is not the first player to regret Chelsea's loss of Costa, as club legend Frank Lampard said in May that the English top flight is not the same without his presence.
“The English game has missed him this season after he rejoined Atletico from Chelsea," he said.
“He is a big player, a big character. Love him or hate him, you have to appreciate that kind of player.
“Chelsea have certainly not looked the same without Costa. Not only is he a big physical presence, he has great quality to score goals."