Atletico Madrid coach Diego Simeone says he blames himself for Colombia centre-forward Jackson Martinez leaving the club this week having flopped at the Estadio Vicente Calderon.
Jackson this week made a shock €42 million move to Chinese club Guangzhou Evergrande, after scoring just three goals in six months at Atletico following his arrival for €35 million from Porto last summer.
Atletico president Enrique Cerezo has said that making an apparent profit of €7 million on a player they did not really need made sense for all parties involved.
However, ahead of Saturday afternoon's La Liga game at home to Eibar, the Colchoneros coach told a news conference that he was sorry that he personally had not been able to fit Jackson into the Atletico XI.
"I am the first person responsible," Simeone said. "[Jackson] did not get the chance to show us his best version. I feel part of that. It is my failure that Jackson did not play, but I am not going to change my way of playing. We spoke openly as men, and from there each person makes their decisions. We wish him luck. I hope he gets back to being the player we all thought he was."
There were reports as the January transfer window began to close that Atletico had made a late bid to bring back Diego Costa from Chelsea, and club chief Cerezo has made public his hopes of the Brazil-born Spain international returning to the Calderon next summer.
Simeone was not getting drawn into such debate at this point: "From Sunday night, after the conversations with Jackson about leaving or not, I had it clear that we would be left with Angel Correa, Fernando Torres, Antoine Griezmann and Luciano Vietto."
Atletico go into Saturday's game against Eibar second in the table, but with their chances of winning the title having been severely hit following last weekend's 1-2 defeat at clear leaders Barcelona.
"We will keep working the same way," Simeone said. "After the game against Barcelona, I thought about Eibar, an opponent who are doing well, they have fast forwards, and full-backs who attack very well. We played a good game at Barcelona, but were not able to win."
Simeone admitted he will have to field a very unusual back four against Eibar, with usual starters Filipe Luis, Diego Godin and Juanfran Torres all suspended after Saturday's game at the Camp Nou, and usual back-up Stefan Savic injuring a hamstring in training this week.
"When we planned the squad we knew we would need all our players," he said. "Jesus Gamez, Jose Maria Gimenez, Saul Niguez and Lucas Hernandez will play at the back. We will try and take positive things for the team."
The squad also includes two youngsters yet to feature for the first team, Nacho Monsalve and Theo Hernandez, the latter the 18-year-old brother of 19-year-old Lucas. It also features Fernando Torres, who returns from an ankle problem, but is likely to be on the bench with his future at the club still uncertain.
"[Torres] returns to the list, he is working with enthusiasm," Simeone said. "If he gets to play I hope he can score, the same as any other forward who might play this game."
Eibar will be without top scorer Borja Baston, who has hit the net 15 times already while on loan from Atletico for the season, but cannot feature due to the terms of that deal.
"[Baston] is not our player, and I have nothing to say about that," Simeone said, when asked about the fairness of such clauses.