MLB matchup analysis

Diamondbacks vs Astros Prediction, Odds and Model Pick

Saturday, September 5, 2026 at Daikin Park · 7:15 PM ET

Pass

LyDia decision: Pass on Diamondbacks vs Astros

Lab Rating
6.4/10
Model lean
Diamondbacks 72.5%
Market probability
49.8%
Model edge
+22.8%
Best moneyline
-105
Sportsbooks checked
6
LyDia model
72.5%
Market
49.8%

The case for Arizona Diamondbacks

Starting pitcher edge: 24 points
LyDia gives Brandon Pfaadt a 24-point edge over Ethan Pecko, driven mainly by BB/9 (2.2 vs 5.5) and HR/9 (1.03 vs 2.20).
Late-inning bullpen advantage
Houston Astros relievers have a 3.56 ERA over the last 7 days; Arizona Diamondbacks relievers have a 2.66. If this is still close after six innings, that gap favors Arizona Diamondbacks.

The case for Houston Astros

Team strength favors Houston Astros
Before any pitcher or bullpen adjustment, LyDia's own team-strength model has Houston Astros ahead (52.0% to 49.1%). The pick still comes from Arizona Diamondbacks once the pitcher and bullpen terms are applied.

Why it is not official

Setup quality below the bar
Lab Rating is 6.4/10, under the 7.2/10 required for an official pick.
Own bullpen carries risk: 6.3/10
The Arizona Diamondbacks bullpen comes in tired. A lead after six innings is less safe than usual.
Cold stretch at the plate
Arizona Diamondbacks is -0.021 wOBA below its own season form.

Why the setup score is what it is

Conviction: 8.78/10
LyDia's win probability for Arizona Diamondbacks (72.5%) is well clear of a coin flip -- this is a real, stated lean, not a guess.
Pitching plan: 26.67/40
Brandon Pfaadt rates 69 on LyDia's pitcher score, judged on its own merits (50-80 is the credited range). That is a strong start on its own, and it earns most or all of the available credit here.
Offense: 28.42/50
Arizona Diamondbacks's recent offensive form clearly outpaces Houston Astros's over the tracked windows.

Why the price is what it is

Team strength: 49.1%
Before any pitcher or bullpen adjustment, LyDia's team-strength model alone makes Arizona Diamondbacks 49.1% to win. Everything below moves the price from this starting point.
Pitcher score gap: 36 points
The pitcher-score gap favors Arizona Diamondbacks by 36 points. This is the biggest single mover of the price -- a large gap moves it a lot, a small gap barely moves it.
Bullpen adjustment: +0.048
The bullpen-fatigue gap between the two pens nudges the price toward Arizona Diamondbacks. This moves the price less than the starting pitchers do, since a starter covers more of the game than the bullpen.
Net effect: 49.1% -> 72.5%
Team strength alone had Arizona Diamondbacks at 49.1%. After the pitcher and bullpen terms, the price is 72.5% -- the same number shown as Model Lean above.
The verdict LyDia passes. The combined Lab Rating did not clear the official threshold.
Read the full model output

The combined Lab Rating did not clear the official threshold.

Game information

MatchupArizona Diamondbacks at Houston Astros
DateSaturday, September 5, 2026
First pitch7:15 PM ET
VenueDaikin Park
Starting pitchersBrandon Pfaadt vs Ethan Pecko
WeatherGame-time forecast: 84°F, 23% precipitation chance, 6 mph wind from NE. This venue has a roof, but the roof status is not confirmed.

Starting pitcher matchup

Full Pitcher Matchup Tool →
Brandon PfaadtDiamondbacks · RHP
vs
Ethan PeckoAstros · RHP
MetricDiamondbacksAstros
Pitching planTraditional starterLimited starter
Expected innings5⅔4
ThrowsRR
LyDia pitcher score (higher is better)6945
ERA (lower is better)3.554.96
WHIP (lower is better)1.141.47
K/9 (higher is better)5.96.1
K-BB% (higher is better)10.0%1.4%
K% (higher is better)16.0%15.3%
BB% (lower is better)6.0%13.9%
BB/9 (lower is better)2.25.5
HR/9 (lower is better)1.02.2
Ground-ball rate48.1%30.6%
Fly-ball rate51.9%69.4%

Pitcher edge: LyDia gives Brandon Pfaadt a 24-point edge over Ethan Pecko, driven mainly by BB/9 (2.2 vs 5.5) and HR/9 (1.03 vs 2.20).

How to read this: the scorecards above name the starters; every number lives in this table.

Strikeout Projections Full strikeout projections →

Brandon Pfaadt strikeouts
4.2 LyDia projected Ks
No K play · -0.3K difference is below LyDia's 0.7K threshold
Market 4.5K · O +130 / U -141 · 6 books
Ethan Pecko strikeouts
2.4 LyDia projected Ks
Official pick: UNDER 3.5K · -1.1K difference
Market 3.5K · O -113 / U +100 · 6 books

Same data source as the Pitcher Matchup Tool, where every starter on the slate is compared side by side.

Diamondbacks are 5-5 in their last 10 and averaging 3.6 runs per game over the last 15 days; Astros are 7-3 in their last 10 and averaging 4.2 runs per game over the last 15 days. Season run differential separates them by almost nothing (-0.02 against -0.25).

MetricDiamondbacksAstros
Last 105-57-3
Last 10 by venue (away team on the road, home team at home)4-6 on the road6-4 at home
OPS, last 15 days0.6550.688
wOBA, last 15 days (hot/cold read)0.2910.300
Runs per game, last 15 days3.64.2
K% last 15 days (lower is better)20.0%22.3%

Last 15 days only. Hot and cold streaks for all 30 teams live on the Stats page.

30-day offense

Full offense tool →
Last 30 daysDiamondbacksAstros
OPS0.7060.654 (-0.069 vs szn)
Runs per game3.64 (-0.756 vs szn)3.85 (-0.652 vs szn)
wOBA (model offense input)0.3120.286 (-0.031 vs szn)
K% (lower is better)20.1% (+0.8% vs szn)21.9%

Over the last 30 days the Diamondbacks have been the better offense, 0.312 wOBA to 0.286.

Season profile

Full Stats page →
MetricDiamondbacksAstros
Record74-6873-69
Run differential / game (team quality)-0.02-0.25
Runs scored / game (offense, season)4.434.52
Runs allowed / game (defense, season, lower better)4.454.77
Season OPS0.7080.723
K% season (lower is better)19.4%21.6%
OPS vs opposing hand (season)0.6810.728

Season-long team quality, not recent form. Run differential and run environment come from the season standings; splits for all 30 teams live on the Stats page, including the run environment table.

Every team on today's slate, on any two axes you pick. Diamondbacks and Astros are highlighted.

Diamondbacks
Combined risk
6.3 Tired
Fatigue
6.8 Tired
Efficiency
6.1 Effective
Astros
Combined risk
7.9 Tired
Fatigue
8.0 Tired
Efficiency
5.2 Average

Risk is what the model actually uses: fatigue blended with how well the pen has pitched. High fatigue with high efficiency is a tired pen that is still getting outs.

MetricDiamondbacksAstros
Fatigue6.8/10, Tired8.0/10, Tired
Efficiency6.1/10, Effective5.2/10, Average
Combined risk6.3/10, Tired7.9/10, Tired
Relief innings, last 7 days23.730.3
Back-to-back arms75
7-day ERA2.663.56
7-day WHIP1.181.42

Fatigue measures workload. Efficiency measures recent run prevention. Combined risk is what the moneyline and totals systems use.

Run total projection

Full Totals Projections →
LyDia projection
5.6
Market total
7.5
Projected away runs
3.2
Projected home runs
1.7
Over price
-123
Under price
+107
Arizona Diamondbacks team total
3.2 projected
Line 4.5 · O +110 / U -129
Under research lean (-1.3)
Houston Astros team total
1.7 projected
Line 4.5 · O +116 / U -135
Under research lean (-2.8)

The model projects 1.9 runs below the market total. A research lean still requires a setup rating of at least 7.0/10. Team totals remain research-only until their graded sample is established.

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