Earlier this morning on Sports Radio KJR, John Schneider revealed to Mitch Levy a little more insight into the behind-the-scenes workings of the Marshawn Lynch retirement. Per Schneider, the Seahawks do not want to let Lynch's dead money affect the team's cap health in 2017. So, when Seahawks file retirement papers for Lynch (or place him on the Reserve-Retired list) before June 1st, the move will open up $6.5M in cap space. Currently, Lynch is still on the books.
All of Lynch's remaining signing bonus ($5M) will accelerate into 2016 and the Seahawks will be hit with a $5M dead money charge. The official cap space for the Seahawks in 2016 would then equal $11,138,186. However, this figure wouldn't represent the true amount of space the Seahawks possess.
When calculating true cap space, one has to figure in the costs of the Injured Reserve, the PUP list, practice squad, and other oddball stuff. Put aside an extra $3M for IR (estimated), $1M for PS, $1M in extra dead money if the you choose to cut a draft pick, and then the two salaries for players 52 and 53. All together, these oddities equal about $6M.
Subtract $6M from $11,138,186 and it leaves the Seahawks with around $5.138M in true cap space (assuming a pre-June 1st retirement designation for Lynch).