Miami will be down a key reserve at defensive end going forward. Redshirt junior Demetrius Jackson will miss the rest of the season, beginning with this week’s game against Notre Dame (8 p.m. ABC), because of a reported knee injury. A UM spokesperson said Jackson injured his “right lower extremity” against Virginia Tech. He had surgery Monday afternoon. UM said Tuesday morning he will be out for the year. The website CanesInsight reported Jackson has a knee injury. Jackson has a history of left knee trouble. He has been healthy and productive this year, though. He is tied for the Hurricanes’ team lead in tackles for loss, with 7.5, for a loss of 45 yards. He is tied for second with 3.5 sacks. He has 18 tackles on the year. He backs up starting defensive end Joe Jackson on first and second downs and plays defensive tackle next to Chad Thomas on third downs. He has played special teams, too. In the spring, his coaches said he looked like a new player after recovering from a knee injury that hampered him in the second half of 2016. Jackson sprained his left knee in Week 3 last year at Appalachian State, played through it, and hurt it worse Oct. 15 against North Carolina. He missed three games and returned, though he later admitted he wasn’t the same player. He sprained the same knee during his redshirt year, 2014. Freshmen Jonathan Garvin and D.J. Johnson will see more action in his absence. Garvin, from Lake Worth High, caused and recovered a fumble with a sack in the fourth quarter against Virginia Tech. He also blocked a punt the week before at North Carolina. Garvin has played in eight games and registed two tackles for loss and one sack. Johnson, UM’s highest-rated 2017 signee, has played sparingly, mainly on special teams.