The Denver Broncos officially placed linebacker Von Miller on season-ending injured reserve Tuesday, and they signed linebacker Brandon Marshall to take his place on the active roster.
Miller tore the anterior cruciate ligament in his right knee during the first quarter of the Broncos' 37-13 win over the Houston Texans on Sunday.
He soon will undergo surgery, and he is expected to need six months of recovery time. Miller could be ready to practice on a limited basis by the start of training camp.
In nine games this season, Miller recorded five sacks. He posted a combined 30 sacks in the previous two seasons, making the Pro Bowl both times.
He was suspended the first six games of this season for violating the NFL's substance-abuse policy and was arrested for missing court appearances for speeding violations.
Marshall, 24, was promoted from Denver's practice squad, where he spent the first 16 weeks of the regular season. As a rookie for the Jacksonville Jaguars last season, he played in five games and made two tackles. He was Jacksonville's fifth-round draft pick in 2012 out of Nevada.
Denver replaced Marshall on the practice squad by signing wide receiver Nathan Palmer. The 24-year-old played five games for the Indianapolis Colts in 2012, making one reception for minus-4 yards. He spent a portion of the 2013 season on the Miami Dolphins' practice squad.