When athletic, agile defenders like Boston’s Jayson Tatum and Jaylen Brown play right up on the Raptors’ Pascal Siakam in isolation it serves two purposes. The first, obviously, is it stops him from stepping comfortably into a jumpshot. The second, considering the real strengths of Siakam’s game, is much more important; it forces him to tighten up his handle, slowing him down enormously.
When Siakam gets to play with the ball out in front of him he’s one of the fastest players in the league, which is part of what makes him such a weapon in transition. When forced to tighten things up he’s better than most forwards, which has allowed him to dominate bigs switched onto him in isolation, but high level wing defenders like Tatum and Brown have had no trouble containing him, especially in this Raptors-Celtics series. So how do we get Siakam up to top speed in the halfcourt? Is his biggest strength doomed to only be of use in transition?
How the Raptors could go about getting Siakam opportunities to use his speed to drive to the rim in the halfcourt was a topic of conversation following Siakam’s dud Game 1, in which he looked notably abysmal in the post.
The Celtics don't have real rim protection. Use Siakam's speed to attack the paint from the perimeter— a. :( (@Swarlayzers) August 30, 2020
I, for one, was worried that any effort to use Siakam in this way would lead to the Celtics gapping Siakam like he was Giannis Antetokounmpo or Ben Simmons, daring him to shoot. But, after Game 2, I had to tip my hat to Celtics’ coach Brad Stevens for finding a different and even more effective way of completely nullifying the Raptors’ attempts to get Siakam going as a slasher.
The Raptors did indeed put Siakam in more ball-screen actions in an effort to get his downhill attack going in Game 2. Their initial attempts to do this primarily involved Fred VanVleet screening for Siakam, likely with the idea that the Celtics would be unwilling to switch the diminutive Kemba Walker onto Siakam. A full-on switch here could allow Siakam to attack Walker in the post, even as it takes away his ability to drive hard to the rim. To counteract both possibilities, the Celtics switched every screen anyway — but only for a split-second.
Walker stepping up halts any side-to-side momentum Siakam developed jogging into the screen, preventing him from translating that into a downhill burst of speed he could use to slip by the wing defender. Meanwhile, the Celtics trusted that Walker would have enough time to recover because VanVleet, undersized as he is, is evidently not a threat to roll, and thus would have to pop to the perimeter. Notably, the point he would have to pop to is directly behind Siakam, and as Siakam hits the point of the screen with the goal of accelerating to his top speed, he’s naturally going to have some degree of blinders on. If Walker contains and recovers in time then the screening action results in Siakam being squared up against Brown or Tatum in isolation, a consistently detrimental matchup throughout the series. In short, all that action gets wasted.
In these cases, the Celtics understand that VanVleet was mostly being used as a decoy to give Siakam an opportunity to accelerate. They simply didn’t trust Siakam to make the 180 degree spin and pass enough to punish their tactic of switching and scrambling. It’s a unique tactic, different from a usual stunt-and-recover, which is used to deny a pull-up jumpshot, and to allow a trailing defender (one who fought over the screen) to get back in the picture. With Brown going under instead, this really is more of a split-second switch. Siakam still found some degree of success driving to the rim in the first half of Game 2, but it was almost entirely out of the triple threat position, usually attacking a Brown closeout, where he could accelerate and slip his shoulder by Brown as he changed directions.
In the second half the Raptors changed things up by trying to run the same side-to-side into downhill drive pick-and-roll but with Marc Gasol screening instead of VanVleet. The Celtics’ defensive approach to this play remained the same despite the change in personnel, with Daniel Theis jumping out high and then shuffling back to Gasol. This only exacerbated the problems the Raptors had running this action with VanVleet in the first half, as the threat of a roll was no more present with Gasol than it was with VanVleet, while the threat of a pop was severely diminished.
Again, the coverage here took advantage Siakam’s predictability, with the added problem of Gasol’s passiveness and lack of speed and athleticism. A young, spry big man might spin off of his smaller wing defender the second they pick him up and rush for the front of the rim, where their size gives them an advantage hunting down a lob. Imagining Gasol doing this is hilarious, of course. The moment he’s bumped by Brown or Tatum his subsequent actions become fairly predictable. He’s highly liable to float into the space just above the foul line, and to hesitate if given the opportunity to take a midrange shot, even against a late, recovering contest (and that’s if he looks at the rim at all).
But none of that really matters, because, just as when this screen was guarded by Walker and set by VanVleet, the way Siakam approaches the screen means Gasol is unlikely to ever catch a pass in this scenario, at least not until after the Celtics have recovered. Again, that’s not to say Siakam is a bad or unwilling passer, it’s simply an acknowledgement that he is approaching the ball-screen with his head down, looking to accelerate as fast he can in the opposite direction from where he would need to pass. As a function of what the Raptors are trying to acheive with this ball-screen (getting Siakam going downhill) he will necessarily be fairly single-minded when turning the corner.
This illustrates the real reason this coverage works for Boston: the one-dimensional nature of this play. It is designed to one end, and one end only, a Siakam drive where he is allowed to build up momentum in advance and slide his shoulder by the defender. Gasol and VanVleet all but decoys here, only present to give Siakam the step he needs to reach his top speed. Thus, the Celtics can totally sell out on shutting down the Siakam drive, while doing the absolute bare minimum to stop Gasol or VanVleet. If the Raptors’ approach offensively dilutes down to “we need to get Pascal going” then it will inevitably be rendered ineffective, simply as a result of being too predictable.
So, circling back to the tweet way up at the top, how do the Raptors take advantage of the Celtics’ lack of real rim protection? The answer is not with Pascal Siakam. Siakam is too well defended in this series. There are three players in the Celtics’ starting lineup in Jaylen Brown, Jayson Tatum, and Marcus Smart who the Celtics will switch interchangeably onto him. He has been repeatedly stifled in the post, and unable to get anything going towards the basket as an initiator in the halfcourt. Brown, Tatum, and Smart are just too good defensively for any actions directed at them to be a reliable source of halfcourt offense. The Raptors must attack the Celtics’ weakest defender consistently, which means they have to go at Kemba Walker as much as possible. Specifically they have to involve Walker as the on-ball defender and not as the man defending the screener. The good news is that’s what they did on Thursday night in Game 3.
To attack Walker the screen has to not be switchable, so, again, the Raptors are going to have to do it with Gasol (or Serge Ibaka) as the screener. This is going to put a heavy onus on Gasol to provide more interior scoring than he has all year. He’ll need to roll to the rim aggressively and look to score whenever he catches the ball inside. Again, Thursday night showed some very positive signs in that respect, as Gasol was 5-of-6 inside the arc, with most of those attempts coming on rolls to the rim. He’s able to get these rolls because the vast majority of screens with Walker see him being taken out of the play, leaving Theis, or whoever the Celtics’ big is, trying to defend the rest of the play 2-on-1, all but guaranteeing a good look at the rim for somebody. It may be just Basketball 101, but it proved effective in Game 3, as Raptors guards Kyle Lowry and Fred VanVleet combined to go 15-of-24 on their two-point attempts, several of those attempts coming after successfully pulling away from Walker in the pick-and-roll.
So, simple offense. More big-small pick-and-rolls. But where does that leave Siakam? Likely, it seems, in an ancillary role similar to the one he held down last year for the Raptors. On defense he has the opportunity to make Brown’s and Tatum’s lives as difficult as they’re making his, something he showed off last night with spurts of excellent defense in the second half (botched last-second rotation onto Theis notwithstanding).
On offense look for Siakam to score on spot-up attempts, in transition, and against mismatches when he finds them. But this is a nightmare series for him offensively. Siakam is simply too well defended to fulfill his usual responsibilities as a creator. He could get an opportunity to shine later in the playoffs, but to get there in the first place he’ll likely need to take a step back for now.