Cubs vs. Diamondbacks Prediction: Eduardo Rodriguez Has the Edge in Chase Field Finale

The Cubs have already banked the series and the NL Central cushion — now they just need a stopper against a Diamondbacks lineup that’s found some fight in the desert heat.

Quick take:

• Pick: Diamondbacks +1.5
• Why: Eduardo Rodriguez has been the best pitcher on either roster this month, and Chicago’s bullpen has been leaky in the late innings of this series
• The number to watch: Rodriguez’s 2.61 ERA, the best of any starter in this series

Chicago rolls into Chase Field for the rubber match at 76-56, still comfortably ahead in the NL Central and with one of the best run differentials in the National League at plus-121. Arizona, at 69-63, is fighting to stay alive in the NL Wild Card picture, sitting a game and a half back of the final spot after a 5-5 stretch over their last 10 games.

This series has already delivered its share of drama. The Cubs put together a dominant offensive stretch out west before arriving in the desert, then dropped a tight 5-4 decision on Monday that snapped their momentum right as it looked like they might sweep. Pete Crow-Armstrong, who’s been the engine of Chicago’s offense all year, went hitless in that loss — a rare quiet night for a center fielder who’s racked up 33 home runs and 32 steals this season, good for fourth in the NL in homers and a slash line of .278/.375/.550 that ranks among the best at his position.

Both clubs enter this finale with something real on the line, even if the standings gap makes it look lopsided on paper. Chicago is jockeying for playoff seeding rather than a division spot at this point — the Brewers still sit ahead of them in the Central — while Arizona is scrapping for its postseason life against San Diego and a handful of other Wild Card hopefuls. That desperation gap matters in late-August ballgames, when one team is playing loose and the other is playing like every out counts.

What the Market Is Saying About This Finale

Books have this one shockingly tight for a matchup between a division leader and a team fighting for its playoff life. Chicago opened as a modest favorite around -110 on the moneyline with Arizona sitting near even money, and the run line has the Cubs at -1.5 (+154) against the Diamondbacks’ +1.5 (-185) — meaning the market thinks this is a game the Diamondbacks can easily keep within a run or two, if not steal outright. The total sits at 8.5, and with both bullpens getting stressed over the first two games of the series, there’s a case for the over sneaking through late.

Boyd vs. Rodriguez Is the Real Story Here

Matthew Boyd takes the ball for Chicago at 8-2 with a 4.15 ERA, solid but clearly the softer arm in this pitching matchup. Eduardo Rodriguez, meanwhile, has been arguably the best story in Arizona’s rotation this season — 13-4 with a 2.61 ERA, numbers that would headline most staffs in baseball. When a pitcher with that kind of season-long consistency gets a home start against a lineup that’s cooled off after an offensive explosion, the raw stuff mismatch narrows fast.

Corbin Carroll remains the engine for Arizona’s offense, hitting .251 with 18 home runs and doing damage against left-handed pitching all year, which matters directly against the lefty Boyd on the mound today. Nolan Arenado has added pop late in the summer with 21 homers, and Gabriel Moreno’s .381 on-base percentage out of the nine-hole-turned-three-spot has quietly kept Arizona’s lineup churning even during their rougher stretches.

Rodriguez has not allowed more than three earned runs in a start since the calendar turned to July.

That kind of stretch of dominance is hard to bet against at home, especially with a division-race Cubs club that’s already clinched the emotional edge in this set and could be tempted to play loose. Boyd has been serviceable, but his 4.15 ERA and recent barrel-rate concerns (opponents are squaring him up more than his season averages suggest) make him a real beatable target for a lineup with Arizona’s pop.

Chicago’s lineup still has plenty to worry about beyond Crow-Armstrong. Seiya Suzuki has been steady all year at .269 with 22 home runs, Alex Bregman has provided a professional at-bat presence in the middle of the order, and Ian Happ’s power (22 home runs of his own) gives the Cubs length from top to bottom. But this is a group that has looked mortal against sharp right-on-lefty-caliber pitching in recent weeks, and Rodriguez fits that profile as well as anyone Chicago has faced this month.

The bullpens are the other variable worth watching. Both relief corps have logged heavy innings across the first two games of this series, and neither manager wants this one turning into extra innings. That raises the stakes on both starters going deep — advantage Arizona, given Rodriguez’s track record of working into the sixth and seventh inning consistently, something Boyd has been more hit-or-miss with this season.

Prediction and Best Bet

Chicago still has more talent up and down the roster, and Crow-Armstrong is always one swing from flipping a game, but Rodriguez on the mound at home is the deciding factor here. Look for Arizona to keep this competitive from the first inning and either steal the finale outright or, at minimum, cover comfortably.

The pick:

1. Prediction: Diamondbacks 5, Cubs 4
2. Best Bet: Diamondbacks +1.5

Fade the Cubs’ name value today — Rodriguez’s arm is the best thing on the field at Chase Field, and that’s usually enough to decide a one-run game. Bettors looking to build this into a bigger card can check the latest DraftKings promo code before first pitch.