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Assessing the Boston Celtics Pick and Roll Defense: Part Two

In the second part of the Boston Celtics pick and roll defense series, their prominent technique of "ice" is analyzed using a combination of film study and advanced statistics.

Kelvin Kuo-USA TODAY Sports

The Boston Celtics have been walking on thin ice this season, but it's not because of the cold and snowy New England winter. In basketball, "ice" is a defensive technique used to guard against the pick and roll. Unfortunately for the Celtics, they have spent more time sinking than they have skating when playing "ice" during the month of February.

In the second part of the "Assessing the Boston Celtics Pick and Roll Defense" series, we're going to take an in-depth look at the Celtics' prominent technique called "ice."

When asked about his team's defensive philosophy, Brad Stevens said, "We ice most of the time, our ideal is to ice as much of the time as possible." Coach isn't lying; in fact, during the month of February, the C's iced on 325 of the 441 pick and rolls run against them, which means they ice nearly 75 percent of the time.

But what does it mean if a team "ices" the pick and roll? To put it simply, the on-ball defender angles the ball-handler into the big man defender on "middle" pick and rolls. The big then sags down near the free throw line, which is meant to invite the offense into taking a low percentage mid-range jumper.

On "side" pick and rolls, the on-ball defender is supposed to angle the ball-handler towards the baseline, where the big man is there to corral him. Again, this is meant to force the ball-handler into trying a mid-range jump shot as opposed to a layup or a pass to an open teammate.

Like anything in basketball, it gets more complicated than that, but the basics are all that is necessary to understand some of the content in this study. However, it is important to read the methodology section from Part One of this series before continuing.


As stated above, the Celtics defended 441 total pick and rolls during 11 games in February and they chose to ice on 325 of them (or 73.7 percent of the time). On 108-of-229 shooting, opponents scored 280 points and shot an above average 47.2 percent.

On those chances, the Celtics had a P4 of 0.86 and a PPP of 1.12. Neither statistic is very good, though their PPP especially leaves a lot to be desired, as it is likely near the bottom of the league.

Boston only forced 51 "resets" and 22 turnovers, which means opponents didn't even attempt a shot 22.8 percent of the time. This is probably a below average number, though no statistics are available for a fair comparison.

But it's important to dig deeper since middle and side pick and rolls are both defended differently, and that's where it becomes more apparent where the Celtics are having the most trouble.

The Celtics iced on 193 middle pick and rolls, allowing 151 points, with a P4 of 0.78 and a PPP of 1.01. The PPP is slightly better than the league average 1.03 PPP on pick and rolls, though the average for "P4" is unknown. Teams are also shooting only 42.1 percent (or 59-of-140), with 15 turnovers and 28 resets.

By comparison, the Celtics have allowed 129 points on 132 side pick and rolls in February. This adds up to a P4 of 0.98 and a PPP of an embarrassingly bad 1.26. Teams are also shooting a ridiculous 55.1 percent on 49-of-89 shooting. However, the Celtics did force resets and turnovers at a similar rate, of 22.7 percent (7 turnovers and 23 resets).


Middle Icing

According to the statistics, the Celtics are an average defensive team when defending middle pick and rolls. This season, NBA teams score 1.03 points per possession on all pick and roll plays, and the Celtics allow 1.01 PPP, which is marginally better.

The reason for this success seems to stem from the fact that the C's do a fairly good job of forcing opponents to attempt shots that they want them to. Ice defense is meant to cause mid-range jump shots, which teams take at a relatively high rate versus the Celtics when they attempt a pick and roll.

More often than not, Boston also forces ball-handlers to the weak side. For example, if a right-handed ball-handler were being used in the pick and roll, the player being screened would angle him off to the left, making him use his weak hand. Players are usually less comfortable doing this, as opposed to using their dominant hand. In the video below, many examples of this can be seen:

Listen closely to the audio, because you'll frequently hear the big man call out "ice" to his teammate defending the ball, which makes him aware that a screen is coming. (This can clearly be heard at the 00:35, 00:41, and 01:50 times of the video.) This communication is important as it allows the entire defense to prepare for the impending play.


The photo above details an ideal situation for the Celtics. Kris Humphries properly calls out "ice," so Jerryd Bayless is aware of the screen from DeMarcus Cousins. Isaiah Thomas accepts the pick and goes to his right (which is his weak side).


Here, Humphries properly sags near the free throw line, which gives Thomas plenty of room to do only one thing: attempt a mid-range jump shot. Meanwhile, Cousins is about to roll to the basket, but both Gerald Wallace and Jeff Green are preparing to collapse down into the paint to help. Jared Sullinger is also there, though he is occupied with his own man.


Thomas ends up taking what the Celtics give him, but Humphries also does a sensational job of closing out and making a strong contest on the jumper. Thomas misses the jumper, but even if he had made it, it's something Boston can live with. Anything is better than seeing Thomas or Cousins attack the rim with a full head of steam.

But that is precisely what beats Boston when icing the middle pick and roll. None of Boston's bigs are truly capable of single-handedly stopping a moving train in the middle of the paint. If it's a talented ball-handler or rolling big, off-ball help is vital. When that happens, it opens up options on the perimeter.

On almost every example in the video above, the Celtics big man icing the pick and roll gets beat badly by the ball-handler. Occasionally, like the first and second plays, no teammates off the ball help on the drive. This is where the C's allow layups, which is the worst-case scenario when playing ice.

Other issues occur when the Celtics allow the ball-handler to get in the paint, and off-ball defenders come in to help. This prevents layups, but it leaves their own man wide-open on the perimeter. In this situation, a defender must close out very quickly in order to contest the shot.


On the play above, the Utah Jazz use Gordon Hayward and Derrick Favors in the pick and roll. Brandon Bass properly calls out ice, and Rajon Rondo adjusts to assure that Hayward dribbles to the weak side. Bass, as expected, zones near the free throw line. If Favors decides to roll, all three of Boston's off-ball defenders are ready to help, though Olynyk is in the best position to stop him at the point furthest away from the rim.


Interestingly, Bass decides to take a step up, as if they were trying to hedge, but that puts more pressure on the off-ball defenders to help on the upcoming roll to the basket.

Favors, as expected, does roll, and Olynyk is forced to hurry towards the paint. Before he even got there, Hayward had made the pass out to the wide-open man on the perimeter. The Celtics can live with a three-pointer from some players, but not Marvin Williams, who is shooting over 40 percent from beyond the arc this season.


Olynyk does everything he can to close out, but Williams drills the jumper. In the books, this will be tallied as a basket allowed by Olynyk, but that isn't fair. He was the one responsible for helping in the event that the play broke down on the other side of the floor, which it did. Had Olynyk not helped, Favors would've had a free lane to the rim for either a dunk, layup, or foul. If anything, he should receive credit for making the proper play.

But the real issue at hand here is the Celtics' inability to stop this simple play without having to help. None of Boston's bigs are quick enough on their feet to make the proper play. For years, the organization was spoiled by Kevin Garnett's shutdown abilities, but now they're left with adequate pick and roll defenders.

Side Icing

To put it simply, the Celtics were terrible at defending side pick and rolls during their 11 games in February. They had a P4 of 0.98 and a PPP of 1.26. That means that the Celtics allow 126 points per 100 pick and roll possessions when a shot or free throw attempted, which is execrable.

Opponents were able to shoot 55.1 percent from the field on side pick and rolls because they got high percentage shots near the rim, or wide-open shots on the perimeter.

Brad Stevens recently said, "sometimes Jimmy's and Joe's are greater than X's and O's," when discussing Sacramento's effectiveness on offense, but that statement also stands true for the Celtics' defensive philosophy. What he's saying is, no matter how good (or bad) a team's X's and O's are, it's the players that make it work more than anything else.

What the Celtics want to do is great, in theory, but the personnel on the team just isn't that good. Avery Bradley, who is by far their best perimeter defender, only played in three games this month -- and he wasn't even completely healthy for them. And at the big man position, none of them are nearly gifted enough to contain the ball-handler and stop their own man by themselves.

One of the most serious problems the Celtics have on the side pick and roll is their inability to keep the ball-handler on the side that the play occurred. When icing this play, the on-ball defender is supposed to turn and attempt to send the ball-handler towards the baseline, instead of the paint.

There, the big man is supposed to engulf the ball-handler for a period of time until the screened defender can get back. That's when the big man will then close out to return to his own man, who originally set the screen.

If that all sounds very complicated, here is a video of how the side pick and roll is supposed to be defended. In a perfect world, this is how the Celtics would like to stop it every single time:

But that rarely happens. The C's aren't very good at keeping the ball-handler contained on the side of the court, and oftentimes they "snake" back to the middle of the floor, where many options are available. This is why teams are so good scoring on the pick and roll against Boston.

"We gotta guard the ball better. We gotta control the ball, stop the ball," said Gerald Wallace. "We put a big emphasis on making that guy that's coming off the screen and roll beat us, instead of having options passing the ball and making plays for himself and his teammates."

But since Wallace isn't afraid to say what he wants, it was worth asking if the big man is at fault for not communicating the pick and roll well enough, or if it was something else.

Wallace explained, "Guys are so good these days in the league, if you call out the ice, they find a way to snake and get back to the middle and create havoc. The main thing we have to do is control the ball, as coach said, to keep the ball on one side and limit that offensive player from having more than one option."

Gerald Wallace didn't point any fingers, because he shouldn't; no single player is responsible for the good or bad things that happen on the defensive end of the floor. Defense is not a one or two-man game, it takes a cohesive unit of five players to properly defend a play.

Having said that, a big man like Kevin Garnett, Roy Hibbert, Dwight Howard, Larry Sanders, or Omer Asik can free the overall defense to play much more effectively.

Since the Celtics are stuck with average defenders at power forward and center, their emphasis of containing the ball-handler and forcing him to make a play himself is nearly impossible. Talented playmakers are able to go wherever they want on the pick and roll against the Celtics, which is why they allow astronomical scoring numbers of 0.98 P4 and 1.26 PPP.

In many of the examples from the video above, Boston let the ball-handler scamper loose towards the middle of the floor, which puts immense pressure on the rest of the defense. From this spot, various options are available: the big throwing the screen has more freedom to either pop for a jumper or roll for a layup, the off-ball defenders are forced to crash towards the paint, which opens up perimeter shooters, and the ball-handler has the option of shooting or attacking the rim.

This is why the lack of an elite rim protector hurts the defense so much. With players like Garnett or Howard, they can be put on an island with a guard or wing, and do a very good of preventing a quality attempt. But the likes of Sullinger and Humphries need help defenders -- this is not a knock on their abilities, they just aren't excellent, and not many players are.

Let's take a look at a play where a spectacular big man would've prevented a high percentage look from ever occurring:


Rajon Rondo gets screened and is unable to properly adjust his body to "ice" the pick and roll. From the start, this play is destined to fail since enormous pressure is already being applied by the Lakers.


The ball-handler and roll man both attack Jared Sullinger, who needs help from his teammates. Brandon Bass makes the right move and comes over, and both Gerald Wallace and Jerryd Bayless must then help to prevent a pass to Bass' man.


The photo above is the face of "help defense." All five Celtics defenders are in the paint in order to prevent an easy dunk, layup, or runner. The issue is that two great three-pointer shooters are left wide open on the perimeter.


The ball is then dished out to the perimeter and Bayless quickly scurries back to contest the shot, which was missed. But corner three-pointers are one of the best shots in the NBA, and it was still a good look despite the miss. Watch the play in real time to the right.

There is no one to blame on defense on this play. Rajon Rondo was quickly screened and didn't have time to adjust, Jared Sullinger was put in a tough spot, and the other three defenders all had to help. But the difference is that having a rim protector makes helping on defense less important.

Just watch the way a defense plays when a top-notch big man guards the pick and roll. Off-ball defenders will "show" towards the paint, but the won't deliberately make their way over in order to prevent a play. KG and Asik are so talented that they don't need the help.

With that said, the Boston Celtics' number one need this offseason should be an elite defensive-orientated center, one who is fleet of foot and able to successfully ice the pick and roll. Otherwise, it'll be another tough season for the defense. Like Brad Stevens said, sometimes it's about the Jimmy's and Joe's, not the X's and O's.

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