Ziyech has battled for regular action ever since making the £35million switch from Ajax in 2020.
The 28-year-old has been linked with a loan deal in the January window, but Blues boss Tuchel has rejected the notion.
“At the moment here in Cobham there are no thoughts about his future,” said Tuchel.
“There are no thoughts about a potential change, swap deal or whatever in the winter. I have talked to nobody about that here in Cobham.
“Hakim was not in my office expressing a wish like this so right now, he is a full member of the squad.
“He is an important guy, a very talented guy, a very ambitious guy, and he’s a full part of our squad. He was last season, he is this season and we expect the very best of him all the time.
“But it’s tough competition. I cannot let everybody play all the time 90 minutes, it’s simply impossible.”
Ziyech starred in Chelsea’s pre-season action, scoring in the Blues’ penalty shoot-out win over Villarreal in the UEFA Super Cup final.
But he playmaking forward lost a lot of time and momentum to a troublesome shoulder injury and is only just now working back to his best.
And Tuchel believes the Morocco star’s situation is very simply explained.
“It’s very easy. I said many times he was brilliant in pre-season,” said Tuchel.
“He had an injury which was a huge setback. He played after the shoulder injury with pain and with huge protection which kept him from being totally free, which is necessary for his game and movements and position and style of play.
“Now he’s stepped up in the last games. We had some injuries and he took the chance to have more game time.
“He was decisive, he assisted, he scored. It’s good.”