The thinking behind Gregg Popovich's replacement of Tiago Splitter with Matt Bonner in the San Antonio Spurs' starting lineup was to get Serge Ibaka away from the rim. When Ibaka made a surprise return to the Thunder lineup in Game 3, he completely flipped the series' momentum to shift it towards the Oklahoma City Thunder's favor.
The logic was there: put in a big man who can command defensive attention from behind the arc aside Tim Duncan, and extract Ibaka's protection from the paint. (Also, any time Bonner gets to play is generally pretty awesome.)
Bonner didn't quite pan out in Popovich's experiment. He finished the game going 0-for-4 in 17 minutes, taking and missing two threes while not really scaring the Thunder enough to pull Ibaka away from the rim. Scott Brooks stuck to his defensive principles, trapping pick-and-rolls and letting Ibaka collapse into the paint to continue protecting the rim. The Oklahoma City Thunder's length and athleticism, as always, were a factor in closing out on Bonner's shots and running him off the line, but he simply couldn't make the Thunder pay for playing off him. When the Spurs came back out to the court for the second half, Pop had pulled Bonner out of the starting lineup.
The flip side of that, however, is that Pop also found someone else to go to. Bonner failed to pull Ibaka out of the paint or otherwise make the Thunder pay, but Boris Diaw did that and more in Game 5.
When Diaw was asked about Bonner's impact on games in the post-game interview, he said:
"The way that Matt is on the court, they've got to be aware of him. He's one of the best shooters in the league, they have to guard a certain way and then that helped us drive the ball a little more effectively and find open shooters."
Bonner didn't have the range last night, but Diaw might as well have described the effect of his own play. He was the x-factor in this game that allowed the Spurs to get back to driving into the lane and set up interior passing, which is really when they're at their best, without Ibaka interfering.
In 28 minutes off of the bench, Diaw had a balanced line of 13 points on seven shots, two three-pointers, six rebounds and three assists. Those aren't dominant numbers, but they speak to his versatility and his game plus-minus of +19 (second on the team behind Kawhi Leonard) tells you all you need to know about his impact on the game.
To be fair to the Thunder, there wasn't a whole lot to blame them on for leaving Diaw open at first. Entering the game, he had shot 3-of-11 from three in this series. He had found other ways to put up numbers, but the key for the Thunder was that Ibaka didn't have to respect him. Diaw doesn't like to shoot the three and much of the rest of his effectiveness gets sapped if the defense can play him loose. In the Game 4 Thunder blowout, Diaw was basically forced to jack up threes in a desperate attempt to try and get Ibaka to stick on him defensively. He finished 2-for-6 and it was mostly painful to watch despite the respectable line.
In this game, Diaw was able to find some offensive confidence quickly and that changed everything. Looking back, the funky spin/reverse layup he hit to start off his night might have been the foreshadowing for what was going to come. Diaw quickly found his jumper, hitting some from midrange and three, and that opened up other options for him and the rest of the Spurs' offense.
The Spurs started spotting up Diaw from three behind pick-and-rolls, sometimes working him into staggered or double pick-and-roll plays to get him open and drag Ibaka out of the paint. Doing those sort of things where both big men come out to the perimeter puts pressure on the ability of the Thunder's bigs to defend the paint, especially since the Thunder play an aggressive 'hard trap' pick-and-roll defense. It was fine before because the Thunder would play off Diaw, but he started his open looks and then they had to respect him.
Here's Diaw's third shot of the game, a three-pointer off of a staggered pick-and-roll:
Look at how Ibaka gravitates towards Tim Duncan as the immediate pick-and-roll defenders trap Tony Parker. Diaw is left wide open on the weak side for the three, and given the way he'd been shooting the three up to this point, it was fine to leave him open and dare him to make it.
Except, he did that and he kept doing it. Diaw was knocking down jumpers and even attacking close-outs to create good looks for himself, and the Thunder eventually had no other choice than to increase their defensive attention on to him.
Upping attention on Diaw is playing right into the Spurs' hands and it frees up the stuff they really want to do, which is create space on the floor and open the driving and passing lanes to get the ball where they want it. The Thunder know the priority for Ibaka needs to be defending the rim if they want a chance to win, and even when Diaw was on, they weren't silly enough to pull Ibaka from the rim altogether. Still, a few extra feet from the rim created by the threat of Diaw can be the difference when it comes to drives by Tony Parker or Manu Ginobili.
Also, lest we forget, Diaw's a pretty good passer himself and he's going to hit the open man that the Spurs' system will generate. Here he turns a wide open shot from the top of the arc into a wide open layup for Duncan:
Ibaka was integral to the Thunder's two wins in this series, and if the Spurs have truly neutralized him with Diaw, then the Thunder might have a hard time working their way out of this one. Because of a lack of impact (and probably also because he's a hurt player in a blowout, but that hadn't affected his minutes in the last two games that much), Scott Brooks cut Ibaka's minutes a bit short in Game 5. I can tell you right now that less Ibaka isn't the answer. They need his presence in the paint, plain and simple.
Figuring out how to deal with Diaw is difficult, though. He's an extremely versatile player that Gregg Popovich has learned to utilize perfectly. Diaw has the strength to bother with Kevin Durant in the post, and the Thunder can't stick a traditional big on Diaw because of his perimeter skills.
Maybe the Thunder will choose the lesser of two evils and go small after all, letting Diaw have the post-ups and keeping Ibaka in as the 5 defending Duncan. Simply daring Diaw to repeat this performance again also sounds like a decent idea with the way the rest of his series has gone, but with the Thunder facing elimination now, Brooks would have to be quick to adjust in Game 6 if things go awry right away.
It's not even a given that Diaw will start Game 6. He's a big part of the Spurs' second unit, where Patty Mills is much more of a gunner than Tony Parker and Diaw serves as a counterbalance. The Spurs probably could do worse than leaving Matt Bonner in, and using Diaw off the bench. That's semantics, though – Diaw is going to make an impact to support Parker, Duncan et al regardless of whether he's starting or not.