Frenkie de Jong remains doubtful for Ajax's Champions League quarter-final second leg against Juventus, says Erik ten Hag.
De Jong limped out of an Eredivisie defeat of Excelsior due to a hamstring injury but was included in Ajax's travelling squad for the trip to Turin.
The Barcelona-bound midfielder's agent Ali Dursun insisted De Jong's substitution was a precaution, telling De Telegraaf that he would be fit.
But Ten Hag cast doubt on De Jong's ability to face Juve when he appeared at a pre-match news conference on Monday.
"De Jong is still in doubt," said the Ajax coach. "After tonight's training, we will see.
"The fact that he is not training yet is not decisive in terms of whether he will play. We don't test it that way.
"We live hour by hour, day by day. We are willing to take a responsible risk.
"Frenkie has to listen carefully to his body and ultimately I make the decision. We are in a positive way."
The tie is finely poised at 1-1 after David Neres struck to cancel out Cristiano Ronaldo's headed opener in the first leg.
In the last round, Ajax lost 2-1 at home to Real Madrid before stunning the three-time defending champions at the Santiago Bernabeu with a 4-1 victory.
"Juve are the favourites, especially after the Amsterdam result," Ten Hag said. "If we play well, we can overcome any limit.
"[Massimiliano] Allegri is very knowledgeable and has certainly thought of a different way to approach this game compared to last week. We need to improve our tactical plan."
Nicolas Tagliafico misses out through suspension, but Ten Hag was unwilling to give Allegri any clues as to who could replace the left-back, or which player could be tasked with marking Ronaldo.
"[Noussair] Mazraoui can play there, but so can [Daley] Sinkgraven," Ten Hag added. "We can also move [Daley] Blind. We are not going to put a permanent man on Ronaldo – we will never do that."