The Pittsburgh Pirates host the Arizona Diamondbacks on July 26, 2025. First pitch from PNC Park is scheduled for 6:40 p.m. EDT; the game will be broadcast on ARID.
Find my MLB betting preview and Diamondbacks vs Pirates prediction below, as well as probable pitchers, betting trends, injury reports, and more.
My Diamondbacks vs Pirates Prediction
- Diamondbacks vs Pirates picks: Under 9 (-119 Draftkings)
My Diamondbacks vs Pirates best bet is Under 9. Make sure to find the best odds by checking our live MLB odds page.
Diamondbacks vs Pirates Odds
| Diamondbacks Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
-1.5 -148 | 8.5 -122o / -103u | -136 |
| Pirates Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
+1.5 +122 | 8.5 -122o / -103u | +114 |
Diamondbacks vs Pirates Projected Starting Pitchers
| Merrill Kelly (ARZ) | Stat | Andrew Heaney (PIT) |
|---|---|---|
| 9-5 | W-L | 4-9 |
| 2.2 | fWAR (FanGraphs) | 0.1 |
| 3.32 / 3.87 | ERA /xERA | 5.03 / 5.34 |
| 3.48 / 3.57 | FIP / xFIP | 5.34 / 4.65 |
| 1.06 | WHIP | 1.31 |
| 16.6% | K-BB% | 9.0% |
| 44.2% | GB% | 37.1% |
| 91 | Stuff+ | 93 |
| 104 | Location+ | 102 |
The Betting Insider’s Diamondbacks vs Pirates Preview
Arizona Diamondbacks Betting Preview: Trust Kelly to contain Pirates
Merrill Kelly has quietly been one of the most dependable arms in the National League this season. Entering tonight’s matchup with a 9–5 record, a 3.32 ERA, and a 1.06 WHIP, Kelly has delivered consistency and length all year.
He leads the Diamondbacks in quality starts (12 in 21 outings) and has racked up 118 strikeouts across 122 innings while walking just 37 batters. What makes Kelly effective isn’t overpowering velocity but his ability to command the zone, mix pitches, limit free passes, and generate ground balls.
The Pirates' lineup has been beyond bad as of late, holding a wRC+ of just 51 since the start of July, which is far and away the worst in the league. No other team has a wRC+ of below 85 over that span. They are batting .204 and slugging .293, also the worst marks in the league, and have scored just 46 runs in their last 18 games.
Pittsburgh Pirates Betting Preview: Heaney to Get Back on Track
On the other side, Andrew Heaney’s 2025 campaign has veered off course. Once a promising back-end starter, Heaney is 4–9 with a 5.03 ERA and a concerning 1.31 WHIP across 102 innings.
His recent form has been especially troubling; over his last seven appearances, he’s been shelled for a 9.40 ERA and has gone into the 6th inning only twice. His most recent start lasted just over four innings, where he was tagged for seven earned runs. But, 5 of those starts came on the road, where he has been far less effective.
At home, he holds a 3.58 ERA and has recorded a quality start in 5 out of 9 outings. He has shown the ability to navigate through difficult lineups and limit damage when he’s on, and I like his odds to do so tonight at home with a full 5 days of rest. With both teams coming off a poor offensive performance, a few key systems from The Betting Insider have been triggered.
Diamondbacks vs Pirates Prediction, Betting Analysis
Sometimes the best bets are the ones no one wants to make. With only 16% of dollars and 15% of bets backing the under in tonight’s Pirates vs. Diamondbacks matchup, it’s a classic contrarian setup—especially when you realize just how many profitable systems line up behind it.
Let’s start with the strongest: Unders in non-division matchups with low totals where the home team got shut out in their previous game. This exact setup has quietly crushed over time, going 347-234-33 all-time (60% win rate, ROI: 15%) and 18-15 this season (55%, ROI: 5%). Why does it work? Because oddsmakers shade totals down after a team gets shut out, and the public overreacts, expecting a bounce-back in offense. But historically, scoring doesn’t explode the next day—especially when the total is already low, like tonight’s 9.
Then there’s the "neither team scored more than one run in their last game" under system, which is all about continuation bias. Bettors expect regression to the mean—but when two struggling offenses face off, the under often keeps cashing. This spot is 202-132 all-time (60%, ROI: 17%) and 11-6 this season (65%, ROI: 23%). It’s a simple but effective idea: if neither team showed life yesterday, why expect a shootout tonight?
Finally, one of the most potent systems in the portfolio: home teams off a shutout loss, not heavy underdogs, and facing public opposition. That’s the Pirates tonight. This system thrives on mispriced games where the market fades the home side based on short-term results. It’s posted a dominant 272-163-17 record (63%, ROI: 21%), and this year it's even better: 23-8-1 (74%, ROI: 40%).
With all three systems pointing toward a tight, low-scoring affair—and the public pounding the over—it’s a textbook case of value in the under. These models work because they expose market inefficiencies created by recency bias, public perception, and Vegas shading. When they all align like they do here, it’s rarely a coincidence.
Pick: Under 9
Moneyline
We are passing on the ML
Run Line (Spread)
We are also passing on the Run Line
Over/Under
As mentioned, we are taking Under 9
