CINCINNATI -- The Bengals placed starting outside linebacker Thomas Howard on season-ending injured reserve after he tore his anterior cruciate ligament during Thursday's practice, the team announced Friday.

Howard, a seven-year veteran from UTEP, was Cincinnati's tackling leader last season with 120 stops, and started in the Bengals' Week 1 loss to the Ravens on Monday night. He had four tackles, including a sack, and a pass defensed in the 44-13 defeat.

The top candidates to replace Howard in the lineup are Vincent Rey and Dan Skuta. Rey is a special-teams player, while Skuta started three games at middle linebacker last year when Rey Maualuga went down with an ankle injury.

Howard, who will make $2.4 million this season, will be an unrestricted free agent after the season.

To replace Howard on the roster, the Bengals signed linebacker Roddrick Muckelroy. A third-year player from Texas, Muckelroy started three preseason games for the Bengals this summer, posting 17 tackles, including a sack. He was a fourth-round draft choice in 2010 by Cincinnati.

The Bengals (0-1) take on the Browns (0-1) on Sunday.

Information from ESPN.com senior NFL writer John Clayton and ESPN.com AFC North blogger Jamison Hensley and The Associated Press was used in this report.