This appears pretty stupid on the part of MLB. They have to know that this will do nothing but escalate things the next time these clubs meet, right? I'm assuming there will be some behind the scenes communication, but really what can MLB threaten to do that will prevent the Sox from saying "enough is enough" and taking this all out on Tampa.
Through the actions of Price and the umpires, the Red Sox were placed in a uniquely ridiculous situation. They offered a measured response that was far more restrained than what was actually warranted, and as a result are being punished further. And the Rays, who couldn't leave well enough alone and basically admitted intent, continue to escape unscathed.
When people complain about Longo catching a 95mph fastball in the back next time out, they'll need to remember that the Sox tried to be the grown-ups last time and paid the price for it.