The Seahawks have not confirmed this yet, and won't until tomorrow, but apparently right guard Rob Sims tore his pectoral muscle and is out for the rest of the year. That is likely to clear the roster spot needed to sign Billy McMullen, though they are still going to add at least one more receiver.
They are likely to replace Sims with Pork Chop, who will be backed up by Mansfield Wrotto.
They tried Ray Willis at guard last season but he got beat out by Chris Gray and then injured his knee against -- yes, this week's opponent -- San Francisco. Holmgren was pretty complimentary of Willis during Monday's press conference but it seems as if they picture Willis as a tackle in the future and not a guard.