The new Blues boss brought the winger on at half-time during their game at St Mary's, but he removed him before the end of the game, admitting he wasn't happy with Hudson-Odoi's approach to the match.
Tuchel - whose side earned a point thanks to a Mason Mount penalty - said: "I was not happy with his attitude, energy and counter-pressing.
"In a game where it was not easy to create chances, you need to rely on counter-pressing to force errors to get the second ball and get the easy chance. And for that, you need to be totally on and sharp for counter-pressing and I did not feel this with Callum today.
"He missed some opportunities for counter-pressing and lost some easy balls and I had the feeling he was never really in the game.
"You know I trust him a lot as he plays every game for us, but today I was close to him and … I do not know, maybe it was unfair, but I did not get the normal feeling with him today that he can be decisive.
"So it is a hard decision today, but nothing that will stick between us, or stick for long. Tomorrow it will be forgotten and we prepare for Atletico."
Tuchel dismissed the idea that the move will harm Hudson-Odoi's confidence in the long term.
He said, according to Sky Sports: "Everyone has to understand that I make decisions to win games.
"There is no problem that he makes mistakes, has a bad game, or misses, but we can't lack energy even 10 percent or five percent. It's not possible. I know what he can give and it's why I trust him a lot."