According to Adam Caplan, Giants defensive end Dave Tollefson is scheduled to visit the Seahawks sometime tomorrow. Tollefson will be thirty next season and has spent the last five seasons with the Giants as a backup lineman. He's not the biggest guy around (6'4", 255 lbs), but he did register five sacks last year and appears to hold up relatively well against the run. I can't see him being anything more than a rotational backup for the Seahawks, though.
These next two items don't involve the Seahawks, but they do affect two of their NFC West rivals. First off, the Rams' new defensive coordinator Gregg Williams has been suspended indefinitely for his role in the Saints' bounty scandal. Williams is a creative defensive mind with a penchant for assaulting offenses with a barrage of disguised blitzes; not having to deal with his defensive schemes twice a year is a good thing. Also, the 49ers decided they want Alex Smith to sabotage their offense for three more seasons. Granted, his stats for last season looked pretty good, but only because San Francisco relies on an offense designed to limit the damage Smith can do to the team. In case I'm not making myself clear here, Smith remaining with the 49ers as their presumed starter is a good thing for the Seahawks.
More updates will be added as they come in.
UPDATE (4:57): I haven't been able to corroborate this information elsewhere, but Rotoworld is reporting that the Seahawks have signed offensive tackle Frank Omiyale. Omiyale appears to be a solid enough player who can play both guard and tackle, plus he has some experience with Cable's zone blocking system (Omiyale was a backup for the Falcons when Cable was their o-line coach in 2006).
UPDATE (5:08): Well, that didn't take long. Omiyale's signing was just announced on Seahawks.com.