For the Seattle Seahawks, this spring has been about far more than just voluntary practices.

After defensive end Bruce Irvin received a four-game suspension last month for failing a test for performance enhancing drugs, the Seahawks have held several meetings, some led just by players, others run by coaches, and taken other steps to try to prevent other players from making similar mistakes.

"We have extraordinary commitment to what we do on the football field, with our training and our preparation and all of that. Our commitment has been called on to expand to 24-7, that's what it amounts to," head coach Pete Carroll told USA TODAY Sports on Thursday after his team was dismissed following the final meetings of the voluntary organized team activity period. "Everyone is involved in this."

Irvin is the league-high fifth Seahawks player to be suspended under the league's PED policy since Carroll and general manager John Schneider arrived in Seattle in 2010, joining cornerback Brandon Browner (2012), safety Winston Guy (2012), offensive tackle Alan Barbre (2012), and guard John Moffitt (2011).

A sixth player, cornerback Richard Sherman, had his suspension overturned on appeal last December after successfully arguing there had been a flaw in the testing procedure. (Another, former practice squad running back Vai Taua, was suspended by the team for four games in 2011, and the Tacoma News-Tribune reported Taua tested positive for a PED.)