The 49ers placed linebacker Malcolm Smith on injured reserve Monday, ending his season before it even began. Smith, who signed the most lucrative free-agent contract of any 49ers defender in the offseason -- five years, $26.5 million -- tore a pectoral muscle in Saturday’s practice. The recovery time for such an injury typically is five to six months.
Ray-Ray Armstrong, who tore a pectoral muscle last season, likely will step into Smith’s spot at weak-side linebacker but must hold off first-round draft pick Reuben Foster.
The two have different strengths. Armstrong, a former safety, is skilled in coverage while Foster, who played middle linebacker at Alabama, is excellent at attacking the line of scrimmage.