I agree that the developments with Evans and Martin may have turned this question a bit. I mentioned faceitously a couple of weeks ago that JJ already had a hand in ending the Kings careers of a couple of young swingmen in Hedo and Wallace, be a certain irony to bringing him back to retard the development of a couple of more in Evans and Martin.
That said, there would still be a couple of arguments for why you could bring him back --
1) he is still at his age a proven scorer and rugged tough guy type who would be a rock solid trustworthy backup for Peja. If it could convince Rick to let go of his Peja security blanket and actually cut him down to 35min/gm or so it could have long term benefits with a fresher Peja come playoff time.
2) as much as the rooks have impressed, the odds are that a desperate aging JJ would be the more valuable swingman to have come playoff time.
Personally I don't do it -- I just know what would happen there with Rick -- JJ would eat up not only the backup Peja minutes, but as many of the backup OG minutes as possble as well, and Martin/Evans would be largely banished back to the bench. But there are still reasonable reasons why you might. JJ still mgiht give you the best chance at a championship this year, even as he once again messes up your future int he process.