Club-record signing Lukaku was injured by a tackle from Lasse Nielsen that resulted in a penalty Jorginho confidently dispatched to add to Andreas Christensen's opener in Thursday's (AEDT) 4-0 thrashing of Malmo in the UEFA Champions League.
Kai Havertz replaced Lukaku and scored Chelsea's third before playing a role in another spot-kick for the Blues converted by Jorginho, though Chelsea also lost Werner to a hamstring injury.
Chelsea faces the Premier League's bottom side, Norwich City, on Sunday (AEDT), before going up against Southampton in the Carabao Cup on Wednesday (AEDT).
While Tuchel refused to put a definitive timescale on the return of his two first-choice strikers, the former Paris Saint-Germain boss revealed neither will play a part in the two games.
"They're both out for tomorrow, all three of them are out for tomorrow," Tuchel said, also referring to Christian Pulisic, who has been out since suffering an ankle injury while on international duty in September.
"No big news, for Romelu and Timo the thing I can say is they are out tomorrow and the Southampton game and from there we will see what's next.
"I don't think it makes any sense to speculate how long it will be. The fact is you never know, things can be shorter or longer than expected. The one thing I can tell you for sure is both are in treatment, both are positive but are out for the next two games for sure."
Tuchel's decision to play Lukaku against Malmo has been questioned, with the striker having recently left Belgium's UEFA Nations League finals camp early because of muscle fatigue.
With Chelsea's fixtures before the next international break comparatively kind – trips to Newcastle United and Malmo come after the Southampton match, before a home game with Burnley on 7 November (AEDT) – Tuchel was asked if Lukaku's enforced break had come at a good time.
"No, never a good thing, honestly never a good thing," Tuchel continued.
"Mentally, he was a bit overplayed, like other players in our squad, but that does not mean we have to rest them. Jorginho and Mason Mount are in the same spot but they played a fantastic match, so it is like this, they played a lot of competitions with a lot of enthusiasm and personal targets.
"It was not a muscle injury, it was an accident. It is just some percentage, don't underestimate the effort these players go through.
"If you constantly turn the wheel, and the guy wants to turn it, take the responsibility, you can get tired. These little things can make a difference."
Chelsea allowed three forwards, Tammy Abraham, Olivier Giroud and Michy Batshuayi to leave in the last transfer window, but Tuchel has no regrets over that decision.
"You cannot keep a squad of 40 players," he added. "If you think Oli, Tammy and Michy would be in the perfect shape now, but hadn't made it into the 20-man squad, then would they be in the perfect shape?
"Of course in theory it would be like this, but [not] in real life. Nobody wants this to happen, it's a bit of bad luck that we have two injured players in the same position, we have to find solutions, there is no worry about the decisions."