Tuchel was discussing player availability with the media before the FA Cup fifth-round tie against Luton Town when the subject turned to Chalobah, who was on the receiving end of a painful looking challenge.
According to Tuchel, the injury was even more serious than it looked, and required extensive treatment at the end of the game.
"I could not believe what I was seeing after the match," he said. "There was surgery going on in our dressing room, I'm not joking. There was surgery, they were stitching him up. I could not believe it, after the match, after the press conference, when I left they were doing the stitches and I just heard him scream in pain while they were doing it and it looked horrible.
"You could not look away, it was surgery, they did the stitches and it was right there. He was the only one with the doctors and I heard the noise. Seriously, it was a proper cut, very close in the area of the groin, that was open and needed to be closed."
Tuchel also expressed his admiration for the way Chalobah continued the game until the end, despite suffering that injury just under halfway through the 120 minutes, but he remained tight lipped on the defender's chances of featuring in our next match at Luton.
"I could not believe that he played one more minute with this kind of injury, but he played the full match and scored a penalty. This is really big. I would say he showed some balls, but that would be actually maybe the wrong line! He was really brave to do this and full credit to him.
"I decided not to tell if people are playing because we have so many of the players who are overloaded and with these kind of injuries I don't want to give too much information and make preparation for Luton too easy. We are working on it and he was very tough and has my full respect. He showed what it takes."
Just as shocking as the injury Chalobah suffered is the fact that neither referee Stuart Attwell nor VAR felt fit to punish Naby Keita with a free-kick, let alone the red card many felt the challenge deserved.
"In the end we have to understand that VAR is a system but it's also used by humans, so there is maybe all the time a slight margin of error in it,' he added. "You will never find the full solution maybe and we have to accept it.
"You will never find 100 per cent clarity on situations, like the foul on Trevoh. Is it a red card or is it not a red card and is it necessary that VAR interferes or not? This will not end and it's also the beauty of it and it makes the sport so popular."