McCoy missed the 2013 season due to an Achilles tear, though last year's injury was to his right Achilles.
McCoy, 26, has started 14 games since being drafted in the sixth round by Seattle in 2010. McCoy caught 18 passes for 291 yards in 2012.
The Seahawks signed free agent wide receiver Ronald Johnson to take McCoy's place on the 90-man roster.
Johnson has not played in any games since being drafted in the sixth round of the 2011 draft out of USC, where he played for current Seahawks coach Pete Carroll through the 2009 season.
The Seahawks went 13-3 and won the Super Bowl last season.
Anthony McCoy is on IR. New player is Ronald Johnson, WR from USC. — Bob Condotta (@bcondotta) July 31, 2014
- Chris Johnson