FLOWERY BRANCH, Ga. -- Talk about a costly victory for the Atlanta Falcons.
Linebacker Sean Weatherspoon became the third starter placed on injured reserve Tuesday after a win over the St. Louis Rams, though he will be eligible to rejoin the roster in Week 11.
The Falcons (1-1) used the one-time-only designation that allows an injured player to return, but Weatherspoon won't be able to practice for six weeks and can't play in a game for eight weeks.
The announcement came one day after the Falcons placed defensive end Kroy Biermann (torn right Achilles tendon) and fullback Bradie Ewing (separated left shoulder) on the reserve list with season-ending injuries.
Also in doubt: running back Steven Jackson and cornerback Asante Samuel, who both left in the first half with what were described as thigh injuries.
At the very least, the Falcons know they must replace two key players on the defensive side.
Weatherspoon, a first-round pick in 2010, quickly established himself as the leader of Atlanta's defense. He had 13 tackles this season and 306 in his career. Biermann has 16½ sacks in his career, including four last season, and took on the expanded role of outside linebacker when the Falcons went to a 3-4 alignment.
"As I say many times, one man's misfortune is another man's opportunity, and we've got some guys that we expect are going to step up and make some plays for us," coach Mike Smith said Monday.
Replacing Weatherspoon is particularly troublesome, however, because linebacker is the team's thinnest position. There were only four other linebackers on the roster, including two undrafted rookies, before the Falcons signed Jamar Chaney and Omar Gaither on Tuesday.
Chaney, a seventh-round pick by Philadelphia in 2010, played 44 games with the Eagles over the last three seasons, including 23 starts. Gaither also is a former Eagles draft pick, spending five years in Philadelphia before moving to Carolina in 2011 and Oakland last season. He played in seven games with four starts for the Raiders.
The Falcons have greater numbers at defensive end, but getting pressure on the quarterback has been a long-standing trouble spot and there's no one else in a backup role with even Biermann's modest credentials.
Smith was not available for comment Tuesday, an off day for the players, and generally does not provide injury updates before Wednesday unless a player is going to be out for a significant amount of time. Offensive coordinator Dirk Koetter and defensive coordinator Mike Nolan were scheduled to address the media during their regular weekly session.
The Falcons travel to Miami to face the Dolphins (2-0) on Sunday.