Elway, speaking Monday one day after Denver wrapped up the AFC West title, said Miller tore the anterior cruciate ligament in his right knee and will miss the final regular season game and the playoffs this season.
Miller, 24 and a two-time Pro Bowl selection, suffered the injury Sunday during the Broncos' 37-13 win over Houston on a play during which he didn't even go to the ground.
Elway said Miller's injury is "going to be a blow. Von was a big part of the defense.
"Von had done a lot of with to get back to where he is."
Miller played in only eight games in 2013, accounting for 34 tackles and five sacks. He was suspended for first six games due to violations of NFL substance-abuse policies.
Sunday's win over Houston gave the Broncos a third consecutive AFC West title and also a first-round bye in the playoffs. Denver's final regular season game is Sunday at Oakland.
Ohio bar shooting arrested, charged with murder
Duggar sisters unveil Christian dating rules in new book