So right now our 10 man rotation is
Rajon Rondo, Delonte West
Ray Allen, Von Wafer
Paul Pierce, Jeff Green
Kevin Garnett, Glen Davis
Shaquille O'Neal, ?
We have 3 guys who can potentially back up that spot -- Krstic, Jermaine, and Murphy.
Krstic has shown the most chemistry with these guys. He can probably find the greatest fit offensively and provide the most scoring. As we've seen in his first few games with us, he can go off for double digits and really make our offense lethal. Downside is, his rebounding is pretty bad, and rebounding is easily our Achilles heel.
Speaking of rebounding being our Achilles heel, Murphy is an elite rebounder, regardless of what you think about his overall game. There's only 5 guys in the league who have a better career rebounding rate than him, and one of them is our own KG. If he's the backup C, he becomes our best rebounding big in the Big 3 era (besides for KG), and potentially cures our rebounding woes. Downside is, he's pretty rusty, and this has effected his offense.
The big man who could best serve as a Perk imposter would be Jermaine. He's far better defensively than either of the aforementioned bigs. He rebounds better than Krstic but not as well as Murphy. However, he was supposedly contemplating retirement this season, and his health probably just won't let him be a key cog off the bench. He'll most likely be the 5th big man that we bring in for fouls and defensive purposes.
So who do you think will be the backup C? Personally I would like to see Troy become that guy, but I'm not too confident he'll shake off the rust and outshine Krstic, who's playing really well.