Since Tuchel replaced Frank Lampard the striker's playing time has been limited to two starts and one appearance from the bench, the latter of which saw the Frenchman score the first in the 2-0 win over Newcastle on Monday.
"It's too soon to make these decisions, too soon in the season," Tuchel said. "I don't have enough time to make these decisions because I just stated there weeks ago and we need more time to get to know the group better and better and everybody deserves more time to show their value for the group.
"What I can say is that until now is that I am super happy that he is here. He is one of the top strikers in the box, he's physically strong, he has an incredible first touch when he takes balls directly, he is very, very strong on that, he is very strong on headers. He had an amazing game against Newcastle, he is very positive in training, very impressive, and right now he plays a key role in the squad.
"He is a key figure, maybe not because he plays 96 minutes, but the way he behaves and with his experience on a daily basis so far the last three weeks he has a huge impact in a most positive way that we can wish."