On the surface, the Oklahoma City Thunder are doing fine without James Harden. They have a higher winning percentage (.750) in their first 16 games without last year’s Sixth Man of the Year than they had all of last season (.714). Their point differential (+9.0) is the highest in the NBA. Kevin Martin has excelled in Harden’s role, averaging 16 points on 45% shooting, while Kevin Durant and Russell Westbrook continue to grow as players.

With two of the top ten players in the NBA entering the prime of their careers, Oklahoma City will be one of the elite teams out West for many years to come. However, in order to take the final (and most difficult) step as a franchise, they must address a glaring weakness that has reared its head in their last two playoff defeats, both times to the eventual NBA champions. While Rick Carlisle and Erik Spoelstra masterfully manipulated the match-ups in their runs to a title, Scott Brooks was either unwilling or unable to adjust his rotations when it mattered most.

By all accounts, Brooks has done a tremendous job in his time with Oklahoma City. He was the perfect choice for a struggling, young team that needed stability. Under his command, the Thunder methodically became a contender, improving their winning percentage in each of the last five seasons. Brooks never took his eye off the big picture, focusing on showing faith in his players and sticking to a consistent rotation rather than identifying the best possible line-up on a given night.

That philosophy made sense when Oklahoma City was building for the future, but in 2012, the future is now. Durant and Westbrook aren’t on rookie deals; they’re being paid max salaries worth almost $200 million dollars combined. They’re two of the NBA’s biggest stars, battle-tested playoff veterans who have proven themselves in international competitions. The expectations have changed; like Dirk Nowitzki and LeBron James before them, they’re being graded on one thing: championships.

At the same time, the Thunder’s margin for error has diminished significantly. With Durant, Harden and Westbrook on the floor at the same time, Oklahoma City closed playoff games with a virtual All-Star team. Martin is a great offensive weapon, but he can’t replace Harden’s playmaking ability and he’ll need to be protected a lot more on the defensive end come playoff time. In 2012, the Thunder steam-rolled through the Western Conference playoffs with a 12-3 record. With both the Grizzlies and the Clippers improved and Dwight Howard now with the Lakers, they won’t be able to do that in 2013.

Oklahoma City can’t continue operating with one arm tied behind their back, which they’ve done far too often in the last two playoffs. Ever since Kendrick Perkins came in a deadline deal in 2011, Brooks has steadfastly stuck with the same starting lineup: Perkins, Serge Ibaka, Durant, Thabo Sefolosha and Westbrook. Not only does his rigidity stand in stark contrast to Carlisle and Spoelstra’s flexibility, his faith in some of his players, particularly Perkins, is no longer justifiable.

Perkins has not been the same player since he tore his knee in Game 6 of the 2010 NBA Finals. He was never particularly fleet of foot, but prior to the knee surgery, he was still a relatively nimble center who could move his feet and play above the rim. Now, he’s a strictly below-the-rim and immobile player who brings almost nothing to the offensive end of the floor. I’ll grant that he does many things that “don’t show up in the box score”, but when he was in Boston, he did a lot of box score things too! In 2010, his PER was 15.0, his field goal percentage was 60% and he averaged 2.2 blocks a game. In Oklahoma City, he’s never had a PER above 10, a field percentage above 54% or more than 1.4 blocks a game.

He’s still a useful player, if only for his sheer strength when it comes to holding position on the low block. But, in a league becoming more perimeter-oriented every year, that skill is becoming less and less useful. He can’t stick with any big man who can face him up and attack him off the dribble and his lack of speed makes him only a moderately useful help-side defender. Even his rebounding has fallen off a cliff. To put in perspective, he has the same rebounding percentage as Brandan Wright (11.7), who has been such a poor rebounder that the Mavs have chained him to the end of their bench, despite his team-high PER.

Despite all evidence to the contrary, Brooks has stuck with Perkins through thick and thin and it has cost the Thunder dearly. After losing Game 1 of the 2011 Western Conference Finals to a Mavericks team who got no low-post offense from their center, Brooks won Game 2 by benching Perkins and going small. Yet, instead of learning any lessons, he stuck with his big lineup in the next three games, allowing Dallas to race out to huge early leads. The Mavs destroyed the Thunder’s lack of floor spacing every time they used a conventional line-up, but Brooks didn’t adjust until it was too late.

It was the same story in last season’s Finals. One of the biggest storylines was Oklahoma City’s inability to stay with Miami early, as Brooks refused to make an adjustment to counter the match-up problems Perkins had against the Heat’s small-ball unit. With Miami playing Shane Battier, LeBron James and Chris Bosh upfront, Perkins had no one he could guard and no real role in a game that was played from the outside-in rather than the inside-out. The contrast was glaring: Spoelstra micro-managed every minute of the Finals while Brooks treated them as if they were regular season games.

At that level, the margins between winning and losing are so thin that every minute is precious. Just as in 2012, a slight line-up adjustment paid huge dividends in the 2011 Finals. With Dallas down 2-1 against the Heat, Carlisle turned the tide when he inserted JJ Barea into the starting line-up for DeShawn Stevenson. That allowed him to stagger the minutes of his two scoring guards (Barea and Jason Terry) and two defensive guards (Jason Kidd and Stevenson) to keep a balanced perimeter unit on the floor at all times.

That’s where the true value of a coach is tested. For an NBA coach, the hard part isn’t recognizing the correct tactical adjustments; it’s having the respect of the locker room so that the players swallow their pride and do what’s best for the team. It won’t be easy to minimize Perkins’ role, but unless the Thunder are facing Marc Gasol or Howard in the playoffs, it must be done.

The main argument against replacing Brooks is that “if it’s not broke, don’t fix it”. That’s good advice if you’re not a plumber and you want to upgrade your pipes. But if you are a plumber, that’s crazy. You should be able to look past the immediate results and evaluate the process behind them. The process behind Brooks’ decision-making in the last two playoffs has been faulty and that has to be addressed, one way or the other. All roads to an NBA title go through Miami; if the Thunder are going to beat a prime LeBron James in a best-of-seven series, they can’t afford to be outcoached.