Thomas Tuchel has shouldered the blame for Hakim Ziyech's stalled progress at Chelsea.
Morocco forward Ziyech has only featured twice so far under new Blues boss Tuchel, leading to suggestions the ex-Ajax star could seek a summer exit from Stamford Bridge.
But German chief Tuchel is adamant he will need to call on Ziyech as the hectic season unfolds, and challenged the 27-year-old to stay sharp.
"It is my fault actually, not his; it is my hard decisions at the moment as well for Mason Mount, Callum Hudson-Odoi and for Christian Pulisic sometimes in the half positions where we seem the strongest," said Tuchel.
"It is the same for Hakim at the moment and for some other players, there were hard decisions to make. It is never easy but it is a good thing, we have quality to make our decisions.
"There are decisions for other players that means Hakim suffers, I can absolutely understand and agree with that so it is my responsibility and fault in this case that he cannot show more of his potential.
"When I look at the schedule and rhythm for the next games I can be sure that we will need all of our players. No matter how hard things are for you personally, I can't say one bad thing (about) Hakim. He had a good session yesterday and has shown he is ready.
"When the moment comes we expect the best Hakim Ziyech. This is not easy, I can agree and understand but this is how it sometimes is during some moments at a club like Chelsea with a squad that keeps winning.
"It is tradition at Chelsea that many players are on loan. They get minutes somewhere else when they cannot make regular minutes here.
"This is good because it is always the target for me to have players that can make it in different circumstances, that can show their qualities in different cultures and clubs. This is always a good sign.
"We will have this talk in the next weeks and months about the guys who are away on loan but of course I have a general impression of Tomori, which means he has high, high potential.
"But I am not into details right now. This will come when it comes."