Chelsea manager Thomas Tuchel was forced to send centre-back Antonio Rudiger inside five minutes early after he was involved in a heated confrontation with goalkeeper Kepa Arrizabalaga in training.
Neither player was involved in Saturday's shock 5-2 defeat to West Bromwich Albion, after which Tuchel challenged his squad to retain their composure and focus on bouncing back as soon as possible.
Unfortunately for the boss, he was handed an unwelcome problem in training on Sunday as The Telegraph note he had to step in to break up a shoving contest between Rudiger and Kepa, before deciding that the defender was not in the right frame of mind to continue the session.
The tension is believed to have stemmed from a small-sided match in which Kepa took exception to a particularly rough challenge from Rudiger.
The rest of the Chelsea squad stepped in immediately to pull the two apart, and after speaking with both players, Tuchel felt Kepa was the only one capable of completing the session.
Rudiger is understood to have sought Kepa out after training and apologised to him off his own back, and Tuchel was happy to move on from the incident as a result.
It was the second clash of heads Tuchel has had to deal with since the West Brom game. Immediately after the defeat, defenders Reece James and Cesar Azpilicueta are believed to have exchanged more than a few words in the dressing room. Similarly, the pair met up later to discuss the situation and both apologised for their actions.
“We cannot, after 14 games, lose our heads and this cannot take away the trust in the players," Tuchel urged after the West Brom loss. "It was a moment to be calm and honest (in the dressing room) and it will be a hard afternoon and evening for everybody.
“We have to accept the loss together and it is important to deal with it together, and I am part of it. Nothing will change, there was no scheduled group day off apart from for individual players who had travelled a lot, and nothing will change.”
Tuchel is not expected to take any further action against any of the aforementioned players, but it's hardly the best way to prepare for a Champions League quarter-final tie with Porto on Wednesday.
The Blues will fly out to Seville for the away leg of their tie with the Portuguese side, before returning to the same city for their 'home' clash on April 13.