Cubs vs. Diamondbacks Prediction: Chicago Looks to Sweep Series at Chase Field

The Chicago Cubs head into Chase Field on Tuesday night riding a wave of momentum after thumping the Arizona Diamondbacks 7-0 in Monday’s series opener, and first pitch for game two is set for 9:40 p.m. ET. Chicago sits at 76-56, comfortably ahead in the National League Wild Card race even while trailing the Milwaukee Brewers by 5.5 games in the NL Central, while Arizona enters at 69-63, clinging to a spot in the Wild Card picture 2.0 games back but dropping five of its last ten. This series has already been lopsided in 2026 — the Cubs have won all three previous meetings against the Diamondbacks this season — and Arizona will need a response fast to avoid falling further behind in a crowded National League field.

What the Odds Say About This Pick’Em

Sportsbooks see this one as a true coin flip. Both the Cubs and Diamondbacks were listed around -108 on the moneyline as the lines opened Tuesday, with the total set at 8.5 runs and the Diamondbacks getting 1.5 runs on the alternate run line. That’s a notable swing from Monday’s opener, when Chicago opened as a heavier -140 favorite before running away with a 7-0 win. The market has since corrected back toward even money, a sign that oddsmakers view Monday’s blowout as more about a rough Merrill Kelly start than a true talent gap between these two clubs. Bettors weighing a run line play on a pick’em number like this one may want to brush up on how betting odds work before deciding where the value actually sits.

Pfaadt’s Breakout Season Meets a Cubs Offense in a Groove

Arizona hands the ball to Brandon Pfaadt, who has quietly authored one of the more underrated seasons in the National League at 7-1 with a 3.39 ERA. Pfaadt has been especially tough to beat straight up, with his teams winning all four of his starts this year when he’s been the moneyline favorite, and Arizona is 12-1 against the spread in his outings overall. He’ll need every bit of that form against a Cubs lineup that has been scorching hot lately, having put up 19 runs in a rout of Seattle over the weekend before backing it up with another 7-0 shutout of the Diamondbacks on Monday.

Chicago counters with Clay Holmes, who carries a 5-6 record but has been sharp of late, sitting around a 2.49 ERA in his recent outings even though the win-loss column hasn’t always cooperated — the Cubs are just 5-7 against the spread in his starts this season. Center fielder Pete Crow-Armstrong has been the engine of this offense, hitting .278 with 33 home runs, while Seiya Suzuki (.269, 22 homers) and third baseman Alex Bregman (.256, 19 homers) give Chicago a lineup with power at nearly every spot. Ian Happ has also chipped in 22 long balls from the leadoff or middle-of-the-order mix, making this one of the more balanced attacks in the league.

Arizona’s response has to come from a lineup that’s dealing with real attrition. Second baseman Ketel Marte remains on the 10-day injured list with a knee issue, and while he’s reportedly building up activity, he isn’t expected back until the Diamondbacks open a series against Philadelphia on Aug. 31 — meaning he’s unavailable for this series. Third baseman Nolan Arenado, who has 21 home runs on the year, has also been dealing with neck and chest issues and has been in and out of the lineup on a day-to-day basis. On the pitching side, Arizona is already without Zac Gallen, Corbin Burnes and Ryne Nelson, all sidelined with elbow injuries, which has forced the Diamondbacks to lean harder on Pfaadt and a patchwork rotation behind him. Corbin Carroll (.251, 18 homers) and shortstop Geraldo Perdomo remain the engine of what’s left of Arizona’s offense, but replacing Marte’s presence in the middle of the order is no small task.

The head-to-head numbers this season back up the eye test: Chicago has outscored Arizona in all three prior meetings in 2026, including an 8-4 win and a 2-0 shutout back in early May. The Cubs also enter as the better all-around team by run differential, sitting at plus-115 on the season compared to Arizona’s plus-2, a gap that shows up in the win column even on nights when the Diamondbacks compete. Anyone tracking these NL playoff races down the stretch can lean on our full MLB betting guide for a deeper breakdown of how to approach the final six weeks.

Prediction and Best Bet

Pfaadt gives Arizona a real chance to slow down a red-hot Cubs lineup, and a true pick’em price reflects a game that should be closer than Monday’s laugher. But Chicago’s offense has too much thump up and down the order, and Arizona is missing too many key pieces — Marte, Gallen, Burnes and Nelson chief among them — to trust a full bounce-back at home. Look for the Cubs to grind out another close win and push this series toward a sweep.

• Prediction: Cubs 5, Diamondbacks 3
• Best Bet: Cubs on the moneyline

With Arizona’s pitching depth thinned out and its lineup missing Marte’s on-base ability in the middle of the order, the value here is in trusting Chicago’s deeper roster to find a way to win a tight, low-scoring game even without needing to blow the doors off like they did Monday.