Coach Brian Kelly confirmed the injury Sunday in a conference call with reporters. Kelly said Okwara, a team captain, soon will undergo surgery. Okwara sustained the injury on a pass rush in the second quarter and left the field under his own power.
An All-America candidate before the season, Okwara recorded four sacks, six tackles for loss, seven quarterback hurries, two forced fumbles, a fumble recovered and a blocked kick. He appeared in 45 games for Notre Dame and started the past two seasons.
Notre Dame is already without another veteran defensive end, Daelin Hayes. Freshman Isaiah Foskey filled in for Okwara at Duke but may use a redshirt this season and could play only one more game if he does.
ESPN's Mel Kiper ranks Okwara as his No. 6 draft-eligible outside linebacker for the 2020 draft.
Notre Dame next plays this coming Saturday when it hosts Navy.