England Under-21 manager Stuart Pearce had not been due to name his squad until June 1 but Wenger confirmed at a press conference that midfielder Wilshere had already been notified of his selection.
Wenger has repeatedly stated his opposition to Wilshere's inclusion, believing that it is a pointless exercise because the 19-year-old has already established himself in England's senior team.
The Arsenal boss also fears Wilshere could fall victim to burnout after a hectic breakthrough season for the Gunners.
"Jack Wilshere is in the red for a while now and this can be a risk for his health," Wenger said.
"He will respect the decision. He knows that he is nearly at the end of his energy level but he is keen to do well.
"He has played nearly 50 games this year. 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."