Celtics Summer League Playbook: Chest Actions

Part 1 in the Summer League Celtics Playbook series

Before we get into today’s post, a few quick updates.

Last summer, I hit a wall in the offseason. I wanted to post daily but didn’t want to force junk out, so I chalked it up to a learning curve and told myself I’d be better prepared this time around.

Turns out… still learning.

I’m still figuring out how to bring value during the quiet months — especially for paid subs. And yeah, when I don’t post, I kick my own ass about it.

Moving forward — and this goes for future offseasons too — I’m aiming for 2 to 3 posts a week. One free, and one or two for paid subs. If stuff happens — trades, injuries, rumors — I’ll bump that up. But when it’s quiet? That’s the rhythm I’m trying to settle into.

Also: I’m back in the podcasting world.
For those who don’t know, I used to host CelticsPod over at SB Nation. I like to think that was a successful show — I know I had a blast. After leaving that show and losing access to another one I built, I’ve been on and off in the audio/video space for the past year. Between that and some mental health stuff, consistency’s been tough.

But we’re moving forward…
The YouTube channel’s showing signs of life, and the audio feed is live again. I’ll be sending out bonus emails when new episodes drop — and between YouTube and podcasts, that could be most days. So if you want more Celtics content in your life, keep an eye out.

And lastly: I’d love your input. What do you want to read, watch, or debate during the dead zone? Paid or free, I want this to feel like a community.

Alright, let’s talk hoops.

Today, I thought it would be a fun exercise (at least for some) if I shared my favorite actions from the Celtics Summer League run. This is far from an extensive list. Instead, it’s the actions that stood out to me on a first watch through.

During the season, I’ll go back and watch games two or three times. With Summer League, I keep it to one watch through, as what we see rarely translates once the season begins. So, I look for plays, actions and concepts, as those are the aspects most likely to translate.

With that being said, I noticed some trends in the play calls being made, with four actions (and their variants) being run consistently.

• Chest actions, aka “Ghost Flare”

• Zoom actions, aka “Chicago or Pistol”

• Reject actions

• Delay actions

Of course, I’ll also sprinkle some other plays I spotted into this, too.

We’re going to look at one action per day for the rest of the week, starting with…

Chest Actions

During the 2023-24 season, en route to a championship run, Joe Mazzulla began implementing the “Chest” series for his best shooters. The idea is simple:

• A shooter or slasher ghosts an on-ball screen

• As they come off the ghost screen, the big man sets a flare screen

• The shooter or slasher accepts the flare, finds space and shoots or drives off the catch

Boston primarily ran the action for Jaylen Brown in 23-24, as they made use of his ability to pressure the rim and counter the defense if they loaded up.

Fast forward to Summer League 2025, and the Celtics were dipping back into the “Chest” section of the playbook, this time for Baylor Scheierman, who can score off the catch, drive the rock, or make secondary reads.

Unfortunately, Scheierman’s shooting struggles meant that this action rarely worked out as planned — still, I’m all about the process, not the results.

Chest Action

The above clip shows the fundamental version of a “Chest” action. It’s a ghost screen¹ that is followed by a flare screen. As you can see, Scheierman is the intended recipient of this play call. He finds himself in a ton of space on the second side, but his shooting slump means that his shot clanks off the back iron.

Still, from a process standpoint, this was a good opportunity. Scheierman was open-to-wide-open on the attempt, which is the ideal outcome when running something that’s designed to create space and put the rock in a scorer’s hands.

Zoom Chest

When you have a play that’s a staple of the offense, it often becomes necessary to disguise the entry so that the defense doesn’t immediately react and take away the advantage you’re trying to create. One of the easiest ways to do this is to string a couple of actions together, especially if those actions are all core parts of the offense.

In the above clip, you can see the Celtics starting the half-court possession with a “Zoom” action². Once again, Scheierman is the beneficiary. He starts the action in the corner, the Celtics set up like they’re running a “Zoom,” but rather than having Scheierman receive the hand-off, he ghosts a screen for the ball-handler and flows into a flare screen, thus creating a “Chest” action.

Unfortunately, Lofton Jr’s screen was a little too physical, killing the play and giving the Miami Heat control of the ball. Still, you gotta enjoy the physicality when it’s on show. That was one heck of a screen. Maybe Lofton should be trying out for an offensive lineman in the NFL. I hear a few teams are short on depth there…

Ram Zoom Ghost

Sometimes, you can run everything right, and the defense still doesn’t budge. That’s exactly what happens in the above play. Credit to the New York Knicks’ defense on this one.

What I liked about this action, though, was how willing the team was to flow from one set to another, and then to another, in search of finding an advantage. The action starts with a “Ram” screen,³ which was a staple of Boston’s offense under Ime Udoka. From there, the Celtics go straight back into a “Zoom Chest” set, which we looked at above.

When the defense doesn’t budge, and each action is met with resistance, Max Shulga is put on the spot and forced to create off the bounce. And while the outcome isn’t ideal, the process of stringing plays together is an encouraging sign heading into a season where Mazzulla will likely need to have a higher play call ratio than in recent years.

Delay Chest

Same principle here. The half-court possession begins with a chest action; however, once again, the Knicks do a good job of killing the advantage. That puts Amari Williams into the “Delay”⁴. Williams reads the floor, threatens the elbow hand-off, and then feeds the back cut for the easy dunk.

Why Chest Actions Work

Over the last few years, I’ve learned that creating Xs and Os content is more than just naming a play and showing the clips. Without explaining why these plays work, the content lacks substance.

So, I’m making a conscious effort to do better at peeling back that additional layer.

A chest action is essentially two types of screens running in tandem. It’s a ghost screen and then a flare screen.

A ghost screen typically creates some level of confusion for a defense, especially one built on switching principles. Most switching defenses are taught to switch on contact. A ghost screen doesn’t create the contact, but the movement involved can sometimes lead to a switch if communication isn’t up to par.

At best, you create a defensive mistake and build an advantage somewhere on the floor. Usually, though, that confusion is like hitting the pause button on coverage for half a second, which helps generate advantages around the perimeter. Furthermore, ghost screens are a great way of changing the side of the floor — what I mean by that is defenses will often load up on the strong side. If a ghost screen comes from the loaded side and ends on the weak side, there’s less resistance once the ball finds the screener.

A flare screen is designed to give a shooter or slasher some additional space. The screen is set for the receiver to fade (or flare) around the perimeter, often into space as their defender navigates the screen. A switch can counter this, but often results in an on-ball and off-ball mismatch.

When you put those two actions together, you have a space-creating set that puts the defense’s communication under pressure and generates looks off the catch. Let’s go back to that play we saw from Brown earlier.

First of all, we’re focusing on Brown’s movements and how the screening actions help spring him free. As you can see from the above clip, the Ghost screen momentarily freezes his chasing defender, as he waits to see whether he needs to switch. That brief pause gives Brown time to come clean off Kristaps Porzingis’ flare screen and fade into space on the weakside slot.

As the strong side is overloaded to begin this action, Brown has considerable space to work with, especially as Porzingis has his own gravity until Brown begins to make the drive.

Here’s another key wrinkle of the above play…

Take note of Sam Hauser in this action. Watch how his movements mirror Brown’s, consistently providing an outlet passing opportunity to one of the best catch-and-shoot threats in the NBA.

More importantly, for this action at least, watch how Hauser’s baseline cut drags his defender with him, thus creating the empty side that gives Brown so much room to drive off the catch. With no one in the weakside corner, there’s limited resistance on Brown’s drive until he gets into the paint.

And while Hauser’s cut isn’t part of a “Chest” action, it does illustrate how every play has nuance to it, even if it looks the same on the first watch. Hauser’s movement and willingness to mirror Brown make everything else in this action possible. However, the space for Brown to receive the ball and get downhill doesn’t appear without him ghosting the screen and flaring into the weakside slot. The defense was already playing catch-up from the moment Brown ghosted on Derrick White.

Now, let’s look at this from Atlanta’s defensive perspective.

In this clip, we’re tracking the defense. We can see the exact moment Brown’s defender plants both feet on the ghost screen, waiting to see if he needs to hedge, switch or contain before realizing he needs to continue chasing the Celtics All-Star. We can also see the risk Brown’s defender takes when trying to get to the pass while it’s in the air, before Brown turns on the jets off the catch.

At the same time, Hauser’s defender is being dragged to the other side of the court before recognizing the threat Brown poses and rotating over in the paint — albeit too late to make enough of an impact.

And we can see Porzingis’ defender switching onto Brown and shading across the restricted area to pose some form of resistance on the drive.

Unfortunately for Atlanta, the Chest action set everything up. Boston had the advantage, and they turned up the tempo once space had been created. Hauser’s cut added the necessary icing to the action, and the defense was always playing catch-up from that moment out.

So, in essence, a “Chest” action is designed to create confusion from the opposing pick-and-roll defense and immediately generate space to capitalize on that confusion. What happens elsewhere on the floor will then play a significant role in how things unfold after that.

So…That’s “Chest” Actions in a nutshell, and some of the variants I liked from Boston’s Summer League tournament.

I’ll be back tomorrow so we can dive into some of their Zoom actions, and look at why that play is so successful in the NBA, and specifically for the Celtics!

1. A ghost screen is a non-contact screen. The screener “ghosts” the action.

2. A pin-down for a shooter or slasher (scorer) positioned in the corner, which allows the scorer to curl around the perimeter and receive a hand-off near the top of the 3-point line.

3. A down screen (screener facing baseline) for a player who then cuts vertically up the court to set an on-ball screen.

4. A fancy way of saying the big man has the rock at the top of the perimeter, with the rest of the players spacing the floor around the perimeter (Five-Out)