Abraham must start from scratch in his latest bid to beat the injury that has plagued him since the Blues' 2-0 Premier League win over Newcastle on February 15.
And now Blues boss Tuchel has told the England forward to forget about his status in the Chelsea squad until he is fully free of the nagging issue.
"Of course, he needs to be fit, that's correct," said Tuchel.
"Then to take it step by step, through good training performances and to fight his way back.
"The way back is maybe for him to be a substitute and to be hungry and full of quality in training.
"These are the next steps, but now is not the moment to worry about the first XI, as he has been out for many games, unfortunately too many games.
"It is absolutely not his fault and he is hungry to come back and he tries all the time.
"He tries all the time, but this is the risk to push the players back as soon as possible.
"It was an accident in training because we thought he would be in the squad on Sunday. So nobody's fault.
"Now is a kind of restart and we hope he can use the next two weeks to get fit again."
Abraham has fallen down the pecking order of Chelsea's strikers since Tuchel's arrival in January.
With Chelsea repeatedly heavily linked with a summer move for Borussia Dortmund's Erling Haaland, Abraham's position at Stamford Bridge has come under scrutiny.
But Tuchel is simply determined to help the Blues academy graduate back to full fitness before considering anything else.
"He quit training on Friday after a five-minute warm-up so there was more or less no chance he could join the squad," said Tuchel.
"It was the same injury, more or less, but he had a re-injury in more or less the same spot where the first injury was.
"So he is in pain and he had to quit the session after five minutes with no chance he could join us on Sunday."
Oliver Norwood's own goal and a late counter-attack finish from Hakim Ziyech booked Chelsea an FA Cup semi-final clash with Manchester City as the Blues saw off the Blades 2-0 in west London.
Sheffield United spurned two big second-half chances, but interim boss Paul Heckingbottom revealed his pride in veteran Phil Jagielka, who started for the Blades just days after the death of his older brother Steve.
"Everyone should be proud of him," said Heckingbottom of 38-year-old Jagielka.
"Fans, his family, everyone at the club is.
"I'd like to say how well he's handled himself. To put in the performance that he did, I thought he was immaculate from start to finish."