Wenger had asked England not to select the 19-year-old who has started more than 40 games for his club this season.
England Under-21 manager Stuart Pearce has yet to name his final 23-man squad for the June tournament in Denmark. "I have heard that he has been picked," Wenger said on the club's website.
"We have to accept and respect the choice even if I think it is the wrong decision. Jack Wilshere has been in the red for a while now and this can be a risk for his health."
Wilshere made his debut for Fabio Capello's England senior team against Hungary in August and has since become an established figure in the full squad, making four senior appearances. "He knows that he is nearly at the end of his energy level but he is keen to do well," Wenger added.
"He has played nearly 50 games this year so to go to a tournament for me is a massive risk. I am happy if the Under-21s do well because I want England to do very well. I think it is not the right decision but will respect (it) and let him go."
Liverpool striker Andy Carroll, who became the most expensive English player when he moved from Newcastle United for 35 million pounds in January, has also been included in Pearce's provisional squad.
