The Bulldogs went right to Howard on the first two possessions and his free throw was the first point for Butler in the game.
The underdog Bulldogs needed the 6-foot-8 Howard to help contend with Duke's size advantage. The Blue Devils have 7-1 center Brian Zoubek and three 6-10 players, including the Plumlee brothers.
Howard was hurt in Saturday night's semifinal win against Michigan State.
The 2008-09 Horizon League player of the year, Howard is Butler's No. 3 scorer (11.6 points), second-leading rebounder (5.2) and the team's best post player.
His playing status became uncertain after he took two blows to the head in Saturday's 52-50 victory over Michigan State. The first blow came when Howard's head hit the floor after a collision with two players. After returning to the game, he took an elbow to the head.
Coach Brad Stevens insisted Sunday that Howard would not play if it there were any risk to his health.
Butler has played without Howard for prolonged periods throughout its NCAA tournament run because of his tendency to pick up fouls. Howard played just 15 minutes in Saturday's game and was replaced in the lineup by 6-8 Avery Jukes, a senior who transferred to Butler from Alabama, and 6-11 Andrew Smith, a freshman.
Jukes made one start this season, while Smith has averaged 5.1 minutes and played in 23 of the Bulldogs' 37 games.