Like Pavlovic and Arroyo, I believe Murphy gives us insurance at the 4-5. And given what we have (or better put haven't) seen from Shaq, we may well need to cash this policy in the POs.
While not ideal, a 5 man big rotation of JO-Krstic-Murphy-KG-Baby could get the job done. While he's rusty as heck, Murphy can still be productive - he can score and rebound. He's a weak defender, but hopefully could do a decent enough job against the 2nd string Bigs on the opposition.
In a perfect world, we don't see him at all in the POs....