The NFL announced the suspension Tuesday.

Moffitt is on injured reserve after suffering a season-ending knee injury in Seattle's game against Baltimore. He has undergone surgery to repair two damaged knee ligaments.

Players are allowed to serve a suspension while on injured reserve. He will, however, miss his paycheck from the final four games.

Moffitt is a rookie drafted in the third round by Seattle.

Moffitt's agent initially declined to comment at this time regarding the suspension.

Update: John Moffitt's agent, Michael George, provided some information regarding the suspension, saying it relates to the use of medication commonly used to treat hyperactivity. That medication, however, needs to cleared in advance by the league. Moffitt made a mistake in that he did not have that preapproval.

He could have chosen to appeal the punishment, however, that would have potentially pushed the punishment into the 2012 season should his appeal have been denied. Instead, he will miss the final four game paychecks from this season and be available when next season begins.