Chelsea lost the FA Cup final on penalties after a goalless draw.
Kai Havertz missed the game with a hamstring injury. And when Tuchel considered bringing in Werner late in the game, the striker informed him that he had twisted his hamstring himself during the warm-up.
This led to Ruben Loftus-Cheek becoming a makeshift centre-forward, only to be hooked again after 14 minutes.
Tuchel said: “Timo was injured. He felt uncomfortable warming up and said he couldn’t play.
“Kai did one last test. He didn’t train because of his hamstrings.
“We tried everything and did the last test in the morning, but it was no better.”
Tuchel suffered a shootout loss to Liverpool for the second time this season after losing the Carabao Cup final in February.