But the team can't, especially not for the same opportunity cost (since the team won't have cap space regardless). Letting Danny walk really doesn't seem like an option outside a scenario where they trade away some guys to make real cap space. My guess is they only reason why he may opt out (and why he doesn't have an extension) is that PATFO are going to try to fit in as many re-signings as possible and are going to ask Danny's cooperation on that.
I actually had a much longer post in there going through the cap math. But that can be saved for later. We all probably know money will be tight with guys like Forbes and Anderson looking for the first paydays, so they will likely need vets like Danny, Tony and maybe Gay to work within the financial limits to bring back as many guys as possible while also getting a longer-term solution established as the third big.