The defensive scheme for this team over the years has always taken time to get use to. Guys like Krstic, Green, and Murphy dont get this overnight, or in 5 games. Takes time. It's a rotational defense so they'll get better with more games and experiences/situations. I don't judge Krstic or any of them on defense for now. No point. Just like Semih started getting it with time, I see no reason that Krstic can't do the same if not better on the defensive end. He's a veteran and will get it down.
Krstic should be the backup for shaq, while JO sees spot duty occasionally . JO for KG at times, after Baby. Murphy behind them. Murphy more often then not will be down the depth chart , depending on health (BBD/JO) and matchups. For the playoffs, I envision our bigs being merely Shaq, Krstic, KG, and BBD. With BBD or Green closing the games, depending on matchups. JO and Murphy don't see much pt unless foul trouble or injury come about.