The United States international is pushing to start Saturday's FA Cup semifinal against Manchester City after forcing his way back into the line-up of late, scoring three goals in his last four appearances.
Pulisic has been suffering with persistent hamstring issues ever since last August's FA Cup Final defeat to Arsenal, with former Chelsea boss Frank Lampard having said the club were looking to devise a tailored training plan to improve his availability.
The 22-year-old was largely restricted to substitute appearances until this month with Tuchel citing a need to "feel calm, mentally" but he played a key role in last weekend's 4-1 win at Crystal Palace and started again three days later as Chelsea edged past FC Porto to reach the Champions League last four.
Speaking ahead of facing City, Tuchel said: "He made huge progress, he was fantastic in the last games and maybe I cannot explain it better -- to be calm, to trust himself in terms of injury, in terms of his full fitness, capability and bit more calm and self-confidence and being aware that I trust him and these things.
"This is important for him to show his full potential. Once he is aware that he is a huge player and he has now big performances because he has a huge impact physically and in terms of quality, dribbling runs, arriving in the box in crucial moments.
"He stepped up and this is what I know from him and I am very happy about this in the last weeks and games."