IIRC, teams have a maximum of 50 official visits they can request per draft. Seattle had at least Korey Toomer and Jeremy Lane on their official visit list last year among their 2012 draft picks.
From Tony Pauline's Draft Insider:
DE/OLB Rufus Johnson, who totaled 17.5 tackles for loss and 10 sacks last season, looked good from start to finish at Tarleton State pro-day. Johnson measured [6'6"] 6054/266lbs, was timed officially at 4.72 in the forty, posted a vertical jump of 34.5-inches and broad jump of 10′-2”. He worked out at defensive line drills before the Cleveland Browns put him through a battery of linebacker exercises. Teams requested Johnson workout again at the Texas State workout next week, March 26th. Johnson already has official visits set up with the Seattle Seahawks and San Diego Chargers.
Johnson played his football at Tarleton State, a Division II school.