They can sign Leary to a market deal if they want and the opportunity cost is being able to bring in guys for defense. Being able to do what they want doesnt mean they can sign every FA your heart desires.
They can open up $19m. $5m of it will go to the draft picks. McClain, Irving, and the secondary guys are going to take a good amount too. We still need a WR and a DE as well.
those last two are your opportunity cost and given we have Collins on the roster making $550k, it just does not make sense to pay $8+m AAV on top of the $12m Tyron gets, $10m TFred gets, the $5m Free gets and the $12m Martin will demand soon.