Diamondbacks vs. Cardinals Prediction: Arizona’s Hot Streak Meets a Cardinals Team in Freefall

The Diamondbacks are white-hot and the Cardinals are ice-cold, and somehow Vegas still likes St. Louis to snap out of it Thursday night at Busch Stadium.

Quick take:

• Pick: Arizona Diamondbacks +109 (moneyline)
• Why: Arizona is 4-1 in its last five and has already beaten this exact Cardinals team twice in the last week, while St. Louis has dropped four straight
• The number to watch: Cardinals starter Michael McGreevy’s 2.92 ERA is elite, but St. Louis has lost three of his last four starts anyway

Arizona (53-49) rolls into St. Louis fresh off a 15-5 demolition of the Athletics and winners of four of their last five, keeping them very much alive in the NL West race. The Cardinals (52-49) enter this series on a four-game skid, having dropped three straight in Anaheim against the Angels before salvaging a 1-0 win to close that trip. St. Louis sits fourth in the NL Central, a game back of Arizona in the standings and trending the wrong direction at the worst possible time.

Why the Market Still Trusts St. Louis

Books have the Cardinals as home favorites at roughly -130 across DraftKings, Bet365, and BetMGM, with Arizona getting plus money in the +109 to +110 range and the total sitting around 8 to 8.5 runs. The number leans on McGreevy’s surface-level dominance — a 2.92 ERA and 1.10 WHIP over 108 innings this season — against Brandon Pfaadt, whose 4.58 ERA is far more middling even with a tidy 4-1 record. On paper, this reads like a clear pitching mismatch in the Cardinals’ favor.

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The underlying trends tell a different story than the raw pitching lines suggest — Arizona has been finding ways to win, and St. Louis has been finding ways to lose.

Showing 10 of last 10 meetings

McGreevy’s Numbers Don’t Match His Results

Here’s the disconnect: McGreevy has actually faced Arizona already this season, beating the Diamondbacks 5-4 on July 17 with 6.1 innings of one-run ball. But zoom out and the Cardinals have lost three of his last four starts as a team despite him allowing more than two earned runs just once in that stretch — St. Louis’ offense and bullpen have repeatedly failed to back him up. Ketel Marte has been the engine of Arizona’s surge, hitting .256 with 18 home runs and 59 RBIs, while Corbin Carroll (.249, 14 homers) and catcher Gabriel Moreno (.303 average) give Arizona a lineup that keeps grinding out runs even against good pitching.

Arizona has also already shown it can solve this Cardinals team specifically. The Diamondbacks took both ends of a weekend series in Phoenix just days ago, winning 5-3 on July 18 and then grinding out an 8-7 win in extra innings on July 19 — a series St. Louis actually led in games played before dropping both.

The Cardinals have lost four straight games and three of Michael McGreevy’s last four starts, despite an ERA that would suggest the opposite.

That’s the crux of this bet. Vegas is pricing this game off a strong ERA number, not off what’s actually been happening on the field. St. Louis’ lineup ranks 25th in slugging percentage league-wide, and with Jordan Walker (.292, 22 homers) representing most of the thump, the Cardinals don’t have much margin for error against an Arizona bullpen that’s been serviceable and a lineup that’s clearly seeing the ball well right now. Injuries compound the issue — St. Louis is without reliever JoJo Romero (appendicitis) and third baseman Ramón Urías (elbow), thinning out both pitching depth and the infield.

Arizona isn’t fully healthy either, missing ace Zac Gallen (elbow) and outfielders Lourdes Gurriel Jr. and Jordan Lawlar, but that hasn’t stopped the offense from erupting for 15 runs one night and grinding out extra-inning wins the next. Depth pieces have stepped up in the meantime, and manager Torey Lovullo has been mixing and matching around the injuries without much drop-off in production. Fans tracking this series can also check the latest live MLB odds as lines shift closer to first pitch.

Pfaadt’s own numbers are worth a second look too. His 4.58 ERA overstates how he’s actually pitched of late — Arizona has won each of his last two starts, and he’s shown the ability to work deep into games and keep his team in position even on nights when the results column doesn’t flatter him. Against a Cardinals lineup that’s cooled off considerably since the All-Star break, that’s more than enough.

Prediction and Best Bet

Arizona has the recent-form edge, the head-to-head edge against this exact Cardinals roster, and a red-hot lineup running into a team that’s lost four in a row. St. Louis’ pitching numbers look better on paper, but paper isn’t winning games right now.

The pick:

1. Prediction: Arizona Diamondbacks 6, St. Louis Cardinals 4
2. Best Bet: Diamondbacks on the moneyline

Take the plus money and ride Arizona’s momentum — this Cardinals slump has to end sometime, but there’s no reason to bet on it happening Thursday night.