During Jeff Green’s half season in Boston, I was often his biggest detractor. But now that Green is signed, I’m unequivocally happy.

My smile has nothing to do with my blind love for the Celtics, nor does it have anything to do with changing my opinion on Green. I still have serious questions about whether Green can be a building block for the future, in Boston or anywhere else. But on a one-year deal that maintains cap flexibility for Boston in the summer of 2012, keeping Green was the best move Boston could make.

The Celtics will spend $18 million on a backup small forward for one season, Green’s $9 million contract plus the dollar-for-dollar luxury tax the team will have to spend for being significantly over the cap. That’s an insane amount of money for a player who made both of his teams worse last season, but the Celtics did their job — by overpaying Green for one season, the C’s convinced him to sign a one-year deal, rather than a multi-year deal, which keeps their cap space open and gives the Celtics an opportunity to gauge Green’s long-term value more accurately during a one-year tryout of sorts. Boston fans should line up to kiss Wyc Grousbeck’s feet. After a lockout during which NBA owners complained about all the money they were losing, Grousbeck was willing to pay “Kevin Garnett in his prime” money for Jeff Green so the Celtics could hold onto their big-picture vision of limiting salary going into the 2012 free agency period.

Green isn’t a perfect player — people who read the site know I complain about his rebounding, defensive rotations and general laissez-faire attitude — which is why the Celtics aren’t sure he’s the long-term answer, but he’s also better than anybody the Celtics could have acquired using the mini mid-level exception. Richard Hamilton is rumored to have signed a two-year, $10-million deal in Chicago. Marcus Thornton will earn about $8 million per season. The Celtics, if they had not signed Green, would have been looking to add a small forward using a $3 million exception or the veteran’s minimum. At that price, they would have been lucky if the player could tie his shoes without tripping over himself.

Again, Green comes equipped with flaws that have hindered his efficiency and generally caused his teams to play worse when he’s on the court. But he’s a talented, versatile player who still has enough youth that he could theoretically put those flaws in his rearview mirror at some point in the near future. More likely, he will continue to be an average player, someone whose talent tantalizes but production doesn’t always do the same. Either way, on a one-year contract that commits nothing to the future, the Celtics have somehow walked the Jeff Green tightrope and survived, retaining his services and solidifying the bench without committing any cash beyond this season.

Danny Ainge has done a masterful job rebuilding Boston’s bench with limited assets. The C’s decision to overpay Green for one year shows they are not convinced he will be part of their future, but in the present, keeping him on the roster was the best option.