Locked On Celtics - Podcast Summary

Episode Title: Mazzulla DEMANDS Rebounding Improvement | How GOOD to Celtics need to be?
Host: John Karalis (with guest Tom Westerholm)
Date: October 14, 2025

Overview

This episode centers around the Boston Celtics’ ongoing rebounding issues, Coach Joe Mazzulla’s escalating frustration, and the broader question of how “good” the Celtics truly need to be in order to contend given their unique roster construction. John Karalis and Tom Westerholm dissect recent preseason games, Mazzulla’s public emphasis on rebounding, and what realistic expectations should be for the early season as the team works on finding “structure in the chaos.”

Key Discussion Points & Insights

The “JV Squad” Preseason Problem

• Celtics have faced the back half (“JV squads”) of other rosters in three straight games, making takeaways tricky.

• Tom Westerholm notes that while it’s good the Celtics are dominating inferior teams, it's hard to draw conclusions about capable rotation players’ fit, especially defensively (04:03).

  “I’m tired of watching teams like, you know, JV squads go out there and... the Celtics try to, you know, figure out if their varsity team is going to look good against another team’s varsity team that isn’t present.” (04:40 — Tom Westerholm)

Roster Depth and Odd Construction

• Boston has areas of strength (e.g., multiple scoring guards) but glaring weaknesses, notably in rebounding.
• Tom likens the roster depth to a lake “where there’s holes that just kind of drop off all of a sudden.” (05:15–06:28)

Turnover & Rebounding Troubles

• Celtics are committing high numbers of turnovers: 22 against the Cavs, 29 vs. Toronto.

• Rebounding weaknesses persist even against non-elite opponents; defensive rebounding percentage extremely low (64.3%), which would be league-worst by far.

  “Their cumulative defensive rebounding percentage is currently 64.3, which is God awful.” (09:54 — John Karalis)

Joe Mazzulla's Approach & Public Message

• Mazzulla has been visibly agitated, making rapid substitutions after rebounding lapses to send a clear message (10:10–11:10).

• This intensified rotation is as much about finding solutions as it is about motivation and accountability.

  “Joe spent the entire first half of that game... as soon as somebody screwed up, it’s like, boom, get him. Boom, get him. Boom, get him.” (11:10 — John Karalis)

Can the Celtics Ever Be a Good Rebounding Team?

• Both hosts agree: not with current personnel. Improvement is possible with Tatum back (elite rebounder) and/or a trade deadline acquisition, but “passable” is likely the ceiling.

  “Tatum is a great rebounder. Like, elite rebounder. And they don’t have him. And that sucks.” (15:14 — Tom Westerholm)

  “You just look at this roster and you say, this is not great.” (16:42 — John Karalis)

Quotes & Memorable Moments

Joe Mazzulla on Navigating Deficiencies

“[W]hat self awareness do we have to have as a team in an organization about where our deficiencies lie and how can we navigate those together?... How can we develop, you know, an identity that gives us a shot to win, you know, every single night and a process towards that throughout a season?” (17:27–18:09 — Joe Mazzulla)

John’s Analysis

• Karalis stresses the importance of self-awareness for a team with a glaring weakness and frames it as a question of “how not bad at rebounding can they get so they [...] let the other parts of their game cover for that?” (18:09–19:51)

Margins: How Many More Rebounds Make a Difference?

• Small improvements yield big rewards: climbing from 30th to 15th in rebounding comes down to 3-5 extra boards per game.

  “Four more rebounds and you’re kind of there... that’s four baskets they’re probably not getting second chance points [on]... Now you’re at a 14 point swing in a game...” (26:39–27:42 — John Karalis)

• Westerholm points out even halved value (7 points) is game-changing in the NBA’s tight margins. (27:42–28:46)

Offsetting Weaknesses with Offensive Rebounding

• Celtics have been strong on the offensive glass in preseason, at times at league-best rates.
• John notes: being great at offensive rebounding can help compensate for defensive rebounding shortcomings, so long as the net is positive (28:57–29:47).

Structure in the Chaos: Integrating New Pieces

Mazzulla on Building a Functioning Rotation

“If we can find the structure within the chaos and get that, it’ll be difficult for the environment and the opponent over the course of an entire season... The idea is we’re the ones that can practice it every day, and... know the unknowns before our opponent can.” (30:48–31:25 — Joe Mazzulla)

• This process will be tough and slow, especially with new players and the absence of cornerstone pieces like Tatum at present.
• John: “Finding structure in the chaos is difficult, and they’re nowhere close to that yet.” (31:34)

Setting Realistic Expectations

Early Season “Turbulence”

• The upcoming schedule is unforgiving: Philly (with Embiid), Knicks (rebounding monsters), Pistons, Pelicans, Cavs’ full rosters. (31:35–33:03)
• Early losses or struggles should not be cause for panic; growth is expected to be slow as the “Rubik’s Cube” of the rotation gets solved.
• Tom: “This could be a really fun year. Just...give it some time and keep your hopes up. It’s okay.” (37:20–37:33)

Closing Metaphor

• John compares the upcoming season start to a turbulent plane ascent: hold on, it’ll be rough, but “once you get up in the air...you’ll be okay.” (34:51–36:22)

Notable Quotes (with Timestamps)

• On Defensive Rebounding:

  “Their cumulative defensive rebounding percentage is currently 64.3, which is God awful.” (09:54 — John Karalis)

• On Self-Awareness:

  “What self awareness do we have to have as a team in an organization about where our deficiencies lie and how can we navigate those together?” (17:27 — Joe Mazzulla)

• On Margins Matter:

  “You box out like four more times and you go get four more rebounds, and all of a sudden, you’re up there somewhere.” (26:39 — John Karalis)

• Joe Mazzulla on Structure in Chaos:

  “If we can find the structure within the chaos and get that, it’ll be difficult for the environment and the opponent.” (30:48 — Joe Mazzulla)

• On Expectations:

  “This could be a really fun year. Just give it some time and keep, keep, I don’t know, keep your hopes up. It’s okay.” (37:20 — Tom Westerholm)

Timestamps for Key Segments

• Intro & Preseason “JV squad” problem: 03:48–06:30
• Discussion of rebounding/turnovers, Mazzulla’s frustration: 06:30–11:10
• Can they ever be a good defensive rebounding team?: 15:14–16:42
• Joe Mazzulla’s philosophy on team deficiencies: 17:22–18:09
• Calculating the rebounding margin/margins matter: 26:03–27:42
• Offensive rebounding as an offset: 28:57–29:47
• Mazzulla on “structure in chaos”: 30:48–31:25

Tone & Takeaways

The tone is honest, slightly self-deprecating, and realistic—emphasizing the importance of acceptance and adaptation rather than panic about the team’s limitations. Both John and Tom keep the discussion grounded, making it clear that visible preseason weaknesses shouldn’t be ignored, but also that improvement is about small, attainable adjustments—not massive overhauls.

Summary for New Listeners:
If you’re worried about the Celtics’ rebounding (and Joe Mazzulla definitely is), this episode breaks down why it’s a problem, just how much it matters, and why patience is key in the early season. Rather than dramatic changes, expect tweaks, accountability, and a gradual build towards the roster’s best version—just be prepared for a bumpy takeoff before the team finds its groove.