Wilkinson admits visa problems forced their hand.
"It came down to the fact that his P1 Visa was denied," Wilkinson told oregonlive.com. "He will not be joining us this year.
"It was taking too long. We always had a deadline on it and that deadline was extended a little bit.
"Going into the first game of the season, I think it was important that the fans, the players and the coaching staff to know what we've got and what areas we need (to address) without continuing down a path where we don't know what the outcome will be."