Hakim Ziyech will miss Ajax's Europa League round of 32 second leg clash against Getafe on Thursday.
This was confirmed by last season's Champions League semi-finalists ahead of head coach Erik ten Hag's pre-match press conference.
And the Dutchman went into some detail when asked about why the Morocco international - who will officially join Chelsea in a £33.4m deal when the summer transfer window opens - is unavailable for the big game.
"Hakim was able to play the game against Getafe without any problems," ten Hag said. "It only went wrong after that.
"It is not good enough yet. In addition, we do not want to take a risk for 1 game.
"This is an important phase for us in the competition."
Having only just returned to action following the spell on the treatment table, Ajax's decision not to risk Ziyech even in a huge game is good news for his new club.
With that said, Ziyech's absence is a massive blow for Ajax as they seek to overturn a 2-0 first-leg deficit when they welcome the La Liga outfit to the Johan Cruijff Arena.
Furthermore, it could stop the Morocco international from denying Arsenal and Manchester United in the Europa League before reporting for pre-season training at Cobham in the summer.
Looking ahead to the beginning of July, Ziyech has said he can't wait to get started in west London.
"[I am] Happy, proud, I am excited and I cannot wait," he said in an interview with Ajax TV, as quoted by Chelsea's website .
"It [Chelsea] is a big club in a big competition. I like the style of play, they play really attacking football, and that is something that fits me and that is one of the biggest reasons I chose therefore."
Ziyech also said that Frank Lampard was a factor behind his decision to join the Blues, after admitting that he had spoken with the head coach ahead of the move.
"[He played] A big role," he said.
"We had a lot of contact in the last couple of weeks and he gave me a good feeling and that was also big to do with the decision."
