Diamondbacks Look to Bounce Back Behind Pfaadt as Cubs Chase Series Win

by Earl·August 25, 2026

The Chicago Cubs walked into Chase Field on Monday night and tossed a shutout at the Diamondbacks in the series opener. It was a familiar script — the Cubs have owned this matchup for most of the season — and on paper, Tuesday's Game 2 looks like more of the same. Chicago arrives at 76-56 with a plus-122 run differential, while Arizona is a banged-up 69-63 club missing its two best hitters and a staggering share of its pitching staff.

But Earl's model sees a game the market and the public are treating too casually. The projected outcome is nearly dead even. The Cubs are favored — correctly, on the moneyline — but by less than a third of a run. And when a game projects this tightly, there's a very specific way to bet it.

Two Starters, Two Very Different Stories

Pitcher	Record	ERA	WHIP	IP	K	BB	HR
Brandon Pfaadt (R)	7-1	3.39	1.14	98.1	69	24	11
Clay Holmes (R)	4-4	2.39	1.10	52.2	45	18	3

Clay Holmes has been the better pitcher this season by virtually every rate metric you can find. The 2.39 ERA, the 1.10 WHIP, three home runs allowed in 52.2 innings — those are ace-level numbers. His strikeout rate (7.69 per nine) comfortably exceeds his walk rate (3.08 per nine), and he allows fewer hits than Pfaadt (6.84 vs. 8.05 per nine). In a one-game vacuum, Holmes gives the Cubs the clear edge on the mound.

Here's the problem: the Cubs have lost four of his last five starts. Chicago has scored 0, 3, 3, 2, and 1 run in those games — an average of just 1.8 runs of support for a starting pitcher who has consistently kept his team in the game. That's not a Holmes problem; it's an offense problem, and it's precisely the issue Earl's model flags when it notes the Cubs' persistent failure to convert with runners in scoring position.

Pfaadt is the inverse. He's 7-1 with a 3.39 ERA, but he's been more hittable than Holmes — 8.05 hits per nine and 11 home runs in 98.1 innings — and his strikeout rate (6.32 per nine) is below what you'd expect from a front-line starter. He's been fortunate in results and timely with run support. The Diamondbacks have scored 7, 2, 1, 5, and 8 runs in his last five starts and have won four of them.

None of this means Pfaadt is bad. It means the gap between these two starters is narrower than the raw ERA suggests, and the gap between their teams' outcomes — the point spread, as it were — is narrower still.

What Earl's Model Actually Projects

Earl's model projects a 4.3-4.1 Cubs win, a total of 8.37 runs, and a margin of just 0.26 runs. That's essentially a pick'em. The model's lean on the moneyline is Chicago, and that's its highest-conviction play — the expected value reading (+9.16) makes it the single sharpest number on the board at the current price.

But the model also recommends two complementary moves:

Run line: Arizona +1.5. With a projected margin of 0.26 runs, the Diamondbacks are losing by a quarter-run on average. The +1.5 run line covers that gap with room to spare. In a game the model expects to be decided by one run — or possibly go the other way entirely — the run line is the safest way to back Arizona without needing the straight-up upset.
Under 8.5. The model's 8.37 total lands just below the number. Two factors drive that lean. Holmes is one of the best run-preventers in this matchup, with three home runs allowed all season. And Arizona's lineup, without Ketel Marte, Lourdes Gurriel Jr., and Tommy Troy, is a depleted version of what it was earlier in the year.

The model explicitly accounts for the park factor — Chase Field inflates home runs by 8% and overall scoring by 3% — but it also notes that recent offensive rhythms for both clubs point in the other direction. The Cubs' clutch hitting has cratered. The Diamondbacks' lineup is too thin to manufacture the crooked innings typical of this ballpark. The two forces largely cancel out, and the edge tips slightly under the number.

Line Movement Is Telling

The opening moneyline had the Cubs at -112 on the road and the Diamondbacks at -104 at home, with a total of 8.5. The current market shows Chicago at -106 and Arizona at -102. That's a meaningful tightening: the Cubs' implied edge has narrowed from roughly 1.9 percentage points to about 1.0 point. The market is converging on the same conclusion as the model — this game is close, and the price should reflect it.

The total hasn't budged from 8.5, which is notable in a ballpark with a 108 home-run factor. If the market believed this was a slugfest, the number would have crept toward 9 or 9.5. It didn't. The books are holding firm, and the absence of upward movement tells you where the smart money perceives the edge.

The Public Angle, and Why It's Wrong

The public narrative Tuesday will be simple: the Cubs are the better team, they swept the Diamondbacks in May, and Arizona is too injured to compete. That's true on the first two counts and partly true on the third — yet the model still arrives at a near coin flip.

The reason is that the Cubs' season-long dominance has been built substantially against weaker competition. Their plus-122 run differential reflects what happens when you bludgeon teams you're supposed to beat. When the Cubs have faced competitive opponents in low-scoring games — when there's actual pressure on every plate appearance — the situational numbers say they've struggled to convert. A 5.23 runs-per-game average looks great until you need one run with a runner on third and two out in a 3-2 game.

That's the angle sharp bettors should exploit. The Cubs are the better team. They probably win this game more often than they lose it. But they're not winning by much, and the +1.5 run line with Arizona converts that slim Cubs edge into a comfortable betting window. Add the Under on top, and you're playing the same fundamental thesis: close game, low scoring, and value on the side that isn't getting the public's love.

The Bottom Line

Take Arizona +1.5 at the current price. Take the Under at 8.5. And if you want moneyline exposure, the Cubs at -106 carry the model's strongest expected value of the three.

It won't be pretty. It won't be a blowout. The model sees a tight, tense, lower-scoring affair — the kind of game where one swing, one defensive play, or one bullpen inning decides it. That's exactly where Arizona plus the run line and the Under become the sharpest plays on the board. The public will be on the big shiny record. Earl's model is on the math. Follow the math.