The Boston Celtics’ first competition against Blake Griffin was always going to provide excitement. Now, Griffin’s initial game against Boston has become a distant second on the entertainment scale. (Unless Griffin “Mozgovs” Nenad Krstic, in which case he instantly retakes the crown.) The story of tonight’s game has become the debuts of Krstic and Jeff Green, two players brought to Boston at midseason, in hopes of furthering Boston’s chances at an 18th title.

I still don’t understand the trade, or the “logic” behind it, but that doesn’t mean the newcomers add nothing. Green offers the C’s bench a much-needed jolt of energy (and skill), and his versatility provides Doc Rivers with lineup options he hasn’t had since James Posey left.

That doesn’t mean Green will have a Posey-an impact, because the two players are very different. Where Posey excelled as a defender and opportunistic three-point shooter, Green offers less specialty and more variety. He’s not a great defender (or, really, even a competent one), but he can guard both threes and fours. He’s not a great shooter, but he can hit shots. He’s not a terrific playmaker, but he can make plays. He’s not a great rebounder (and, actually, he’s not anywhere close), but the Celtics won’t need him to play so many minutes per game as a power forward.

Off the bench, Green could have quite an impact. If the Celtics hadn’t given up heart and size to secure him, while resting a majority of their title hopes on the O’Neal brothers’ health, I would love the Green addition. For a team that needed athleticism, scoring and playmaking off the bench, Jeff Green provides all that. But, again, the Celtics lost a big piece of their calling card — size and toughness.

Which takes me to Krstic, who does have height. He’s seven feet tall, hails from Kraljevo, Serbia, and started all 47 games he played for the Oklahoma City Thunder this season. But height and position are two of the only things Krstic has in common with Kendrick Perkins. Perk was Boston’s enforcer, while Krstic is a fu-fu midrange shooter. Perk was muscle, while Krstic is finesse (and a balding hair line that makes him look far older than his 27 years).

Krstic, I don’t think anyone would argue, is more skilled than Kendrick Perkins. He also won’t provide nearly the impact Perk had. There’s a reason Oklahoma City needed to trade for Perk a couple days ago. When the playoffs roll around, defense and toughness become more valuable than ever, and teams don’t win championships with Nenad Krstic as their starting center. Is Krstic a stiff? No. But he’s soft, in a way that will hurt Boston in the postseason should Krstic need to play any serious minutes.

The hope is that the O’Neals — or at least one of them — will become healthy enough for Perk’s absence to mean very little. The hope is that Jeff Green will turn Boston’s bench — so inconsistent and meek for much of the season — into a weapon. The hope is that Kendrick Perkins will prove to be expendable, Krstic will play a bit role, and Green will positively alter Boston’s dynamic while potentially becoming a cornerstone of sorts for the future.

For better or worse, the Jeff Green era begins tonight. I don’t know much, but I know I’ll be rooting for the Celtics to prove me wrong.