Nenad Krstic officially signed with the Russian team CSKA Moscow today, a two-year deal that will expire after the 2012-’13 season. ESPN’s Chris Forsberg reports the contract contains no buyout clause for Krstic to return to the NBA, effectively ending any hopes that he might return to the Celtics at some point next season.

It’s official! The captain of the national team of Serbia, Nenad Krstic, signed a two-year contract with CSKA Moscow, until the end of the 2012-2013 season. After seven years in the NBA — with the New Jersey Nets, Oklahoma City Thunder and Boston Celtics, averaging 10.0 points, 5.4 rebounds in 25.2 minutes in 419 regular-[season] games, and 10.4 points, 5.4 rebounds in 25.2 minutes in playoff games — the center decided to come back to Europe to compete at the highest level to win the Euroleague.

Taken in a vacuum, the Nenad Krstic loss would not hurt much. After all, he spent most of his time last season providing fodder for European stereotypes, and specifically the stereotype, “European big men are quite soft and do not appreciate defense.” With the notable exception of Game 5 against Miami (when Krstic played well enough to prompt questions about whether he should have earned Glen Davis’s playing time sooner), Krstic started his Boston career with a bang before fading into mediocrity and worse. By the end of the season, after Krstic became oddly hesitant on both sides of the court, I felt I could count on him for one thing and one thing only: allowing open layups (and dunks) to opposing big men.

The problem for the Celtics is that Krstic’s loss does not come in a vacuum. It comes amid the retirement of Shaquille O’Neal, the likely departure of Glen Davis, and the continued instability of Jermaine O’Neal’s (deteriorating) body. Jermaine, as I write this sentence, remains Boston’s only center. Kevin Garnett makes the only other big man on Boston’s roster, though I suppose some would argue Jeff Green’s ability to play the four (to which I would respond that his “ability to play the four” often ends with bad results, and to which I would also respond that he’s a free agent, albeit a restricted one).

Whether or not you believe in Green’s power forward-ability, and whether or not he re-signs in Boston, the Celtics have a startling dearth of big men entering tomorrow night’s draft. This is where I will remind you that not only did Danny Ainge trade Kendrick Perkins, but he also traded Semih Erden and Luke Harangody for a box of trading cards and a bag of chips. As you can tell, I’m still a little bitter.

Now Krstic has walked away, and the lack of a buyout clause in his contract means he will not return. Rather than expecting Jermaine O’Neal to play 48 minutes in each of next season’s 82 games, the Celtics will make big men a priority in the draft, free agency and trades. You know, unless they want to enter opening night with Avery Bradley as their backup center. Unluckily for the Celtics, quality big men are often the toughest players to find. Re-signing Glen Davis looks more attractive by the day. Doh.