Agger caught Wilshere on the foot with a heavy challenge during England's 1-0 win over Denmark on Wednesday night.
"It was 50-50. You have to go for those challenges," Agger told the Daily Mirror.
"I was going for the ball and I think I got the ball, but the referee didn't."
England boss Roy Hodgson absolved Agger of any blame for the injury.
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