The Eredivisie champion confirmed defender De Ligt was "awaiting a possible transfer" as it announced a 28-man travelling squad.
De Ligt, 19, has agreed personal terms with Juve and is tipped to sign in a deal worth around €70 million ($113 million).
The Netherlands international trained with Ajax as recently as Saturday (AEST), but a breakthrough in negotiations is said to have been reached.
It seems the Serie A side now only has to complete the final formalities before announcing its seventh new arrival of the close-season.
One of the world's most in-demand players, De Ligt was linked to Barcelona, Manchester United and Paris Saint-Germain before Juve emerged as the favourite for his signature.