The Seahawks treat their practice squad like a rotating group of guys on speed dial. Week-in, week-out they'll sign guys to come in so, as best as I can guess, they can either a) evaluate them and possibly find a diamond in the rough or b) use them in a specific role on the scout team to mimic a particular player on the upcoming opponent. I'm not sure whether this is more of an a) or b) scenario, but the Hawks have signed DE Adewale Ojomo and released DT Sealver Siliga.
Siliga was acquired in the trade of John Moffitt to Denver, and my guess he'll be back at some point, but Ojomo is an interesting pickup, or as interesting as any practice squad transaction can be.
Ojomo, 6'4, 270, was undrafted out of Miami in 2012 but signed with the noted defensive-line enthusiast New York Football Giants. He actually stuck with the Giants on their active roster all of 2012 and for Week 1 this year, but was recently released as New York searches for a running back. Seattle seems to like former Giant defensive linemen, so keep an eye on this guy.
Above, you'll find scouting tape of all his snaps from preseason last year. Might give you an idea of what to expect. He's apparently notched 6.5 sacks in his two preseasons with the Giants, so that's fairly impressive.