It is plausible that the Mavs purposely held out KP on the front end of this back-to-back in order to get him into the Boston game. If he plays today then that is certainly what happened. Guess we will find out tonight.
Regarding whether I would trade KP, it is just difficult to assess his value. I would lean towards a neutral asset, but I'm sure quite a few teams would view him as a negative asset. I'm pretty confident that the Mavs could trade him away for expiring contracts and a heavily protected 1st rounder to some team wanting to gamble on his upside. I just don't see how that makes the Mavericks better though.
It wouldn't shock me at all if he is playing at an all-star level during the 2nd half of the schedule. He pretty much did that last year coming off a surgery (mediocre 1st half, all-star level 2nd half). You can't just give that upside away for expiring contracts. Unfortunately, I don't think KP as a centerpiece gets you in LaVine or Beal talks either. I'm not opposed to trading KP if you are bringing back talent, I just have a hard time seeing a trade like that happening.