Gary Tanguay is a complete moron, and should not be allowed to talk about basketball.
If Pierce opts out, the only way to open up that cap space is to let him walk. If they want to keep his bird rights, then they would have no cap space.
Not to mention, even if Pierce did opt out, they would have less than $10 million in cap space, not $18 million.
Again, let me reiterate, Tanguay is a moron. Do not listen to Tanguay.