He suffered the injury on Monday during the team’s first organized team activities session and is expected to miss at least six to nine months.
McCoy was the Seahawks' sixth round pick in the 2010 NFL Draft out of USC.
McCoy saw action in all 18 games last season, catching 18 passes for 291 yards and three touchdowns last year and graded out as the 14th-best pass-catcher at the tight end position in 2012, according to ProFootballFocus.
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The injury to McCoy leaves second-year players Sean McGrath and Cooper Helfet, 2013 fifth-round draft pick Luke Willson, and rookie minicamp signees Victor Marshall and the former professional basketball playing Darren Fells as the five players rounding out the position behind Miller.