Landry started the first four games of the season for the Colts and played on 80.2 percent of the team's defensive snaps, according to Football Outsiders. He has made 19 tackles this season and recorded one sack.
Landry will miss games against the Ravens, division leading Texans, Bengals and Steelers. Two games are on the road, two are at home. He will be eligible to return for the Colts' Nov. 3 game against the Giants at the Meadowlands on Monday Night Football.
Sergio Brown, a fifth-year pro, is listed as Landry's back up at free safety.
Mike Adams is the starter at strong safety, with Colt Anderson behind him.
Antoine Bethea, who started every game at either safety position for the Colts over the last six seasons, signed with the 49ers in free agency.
Landry signed with the Colts in March 2013. He spent the first five years of his career with Washington and played for the Jets in 2012.
The Colts defense is currently allowing the eighth-most yards per play in the NFL, their same rank as last season.
The defense is playing without Robert Mathis, who led the NFL in sacks last season and tore his Achilles tendon while serving a four-game suspension for PEDs.
Indianapolis lost its first two games of the season, but won its last two, both over division rivals. The Colts are second in the AFC South, behind the 3-1 Texans.
- Dan Gartland