I disagree about the cap space Spotrac and OTC have the Seahawks with about 33 million left and the draft will cost about 8.4 and contracts are structure to make the first year cap hit light (if they want to add players). There are teams still in the red for cap space and only 7 teams have more cap space then the Seahawks at this point in time. I feel the Seahawks have lots of flexibility to make various moves for signing players or trading for players if they want to make any moves.
They do have that at $33M, and have not included a lot of the cap hits (undisclosed) for Brown, Fantx2, Harris, Jenkins.. So $33M left, sub $8M (to your point) for draft, $25M, maybe another $3M for injuries, $22M, and with 5 players left let's say that's $2M per (which is insane to think) that takes them down to $12M.