The club initially said the UAE had barred Mori from entering the country because he had an Israeli passport, but later said the club wasn't sure it had requested a visa for him, DutchNews.nl reported Sunday.
"The decision to travel to Abu Dhabi without Mori is understandable but unfortunate," the club said in a statement on its website.
"In retrospect, different organizations have said there were options to make it possible to travel to the UAE with Mori, who is Israeli. The complexity around organizing travel to countries with specific entry procedures in a short space of time meant not all the options were utilized."
"Vitesse regrets the commotion and offers apologies to everyone who feels in any way affected by the decision to exclude Mori."