The two-month grind of the NBA playoffs can be confusing for players: one series you’re indispensable, the next you can’t stay on the floor.

Oklahoma City’s four defensive-minded big men (Kendrick Perkins, Serge Ibaka, Nazr Mohammed and Nick Collison) were crucial to beating Memphis in the second round. The Grizzlies run most of their offense through the low post; Zach Randolph (26.5) and Darrell Arthur (23.7) led them in playoff usage rating.

Dallas, in contrast, has a seven-footer comfortable playing out to the three-point line (Dirk Nowitzki) and two shot-blocking centers (Tyson Chandler and Brendan Haywood) with playoff usage ratings under 10.

A playoff series is a chess match: when one coach makes an adjustment to his normal game-plan/rotation, the other counters, and they go back and forth over seven games until one is out of answers.

The Thunder’s big men aren’t very skilled, so Dallas began doubling off them. And since they weren’t needed on the defensive end, Scott Brooks made the Western Conference Finals’ first big adjustment: going small in the second half of Game 2.

He took Perkins out with 3:27 left in the third quarter and never put him back in; Mohammed didn’t play at all in the second half. Ibaka and Collison took turns guarding Nowitzki, while Kevin Durant played center.

All of a sudden, the floor was wide open, as the Thunder were playing a power forward and four perimeter players. They out-scored the Mavericks by five points in the fourth quarter, with Eric Maynor (a 38% shooter from the 3-point line), James Harden (35%) and Daequan Cook (44%) spacing the floor for Durant.

To regain homecourt advantage and win in Oklahoma City, Rick Carlisle will need a counter. Portland made a similar move against Dallas in their first-round series, going small with only one true big man -- LaMarcus Aldridge -- on the floor. In the ultimately decisive Game 5, Chandler destroyed his smaller defenders, grabbing 13 offensive rebounds.

He’ll have a chance to do that again, as Durant gives up four inches and should have a difficult time boxing him out. Another possible wrinkle is leaving Nowitzki alone on the back-side of the Chandler/Kidd pick-and-roll; since Dirk’s man will stay attached to his hip, there would be no help at the rim to stop the alley-oop dunk.

On the perimeter, the Mavericks can keep JJ Barea, their offensive spark-plug and best penetrator, on the floor as long as Maynor is in. Westbrook, at 6’3 190, and Harden, at 6’5 220, are just too big for Barea to guard, and Dallas has to hide Dirk on Cook.

While Terry is a better shooter, Barea can get to the rim, taking 31% of his regular season shots in the paint compared to 12% for Terry.

Both teams depend on perimeter scoring from their bench, and getting Harden the ball might be the biggest advantage of taking Westbrook out of the game. He had had a magnificent Game 2, scoring 23 points on 6-9 shooting with 7 rebounds and 4 assists.

While Dirk and Durant were the story of Game 1, the series will be determined by each team’s secondary scorers. It’s no coincidence Dallas won Game 1 when Terry had 24 points to Harden’s 12.

Terry may be more experienced, but the importance of playoff experience is vastly overrated. I’ll take the bigger, faster and stronger player, which is why I think Oklahoma City will win the series.

Going forward, if the Thunder are getting the ball to Harden, the Mavs have to take advantage of Maynor’s defense by inserting Barea for Terry. That’s why the Thunder will eventually bring Westbrook back into the fold, not because of any pop psychology silliness being discussed online.

If Brooks wants to get him going while keeping Harden on the bench, he should consider inserting Cook into the starting line-up for Sefolosha. There isn’t a lot of room for Westbrook to maneuver with only one good long-range shooter (Durant) in their starting five, and neither of Dallas’ starting guards (Kidd and DeShawn Stevenson) is much of a threat to create their own shot, making Sefolosha’s defense much less valuable.

It took a lot of guts on Brooks part to keep Westbrook on the bench the entire fourth quarter, a decision that should quiet speculation about his coaching ability. He has received a lot of criticism for Oklahoma City’s often inept half-court offense, but it’s nearly impossible to have nice-looking offensive sets when neither of your two big men are comfortable with the ball in their hands.

NBA coaching is done primarily on the level of strategy (whom to play) and not tactics (how they play), and Brooks’ decision to go small in Game 2 turned the series around.