The St. Louis Cardinals host the Arizona Diamondbacks on May 23, 2025. First pitch from Busch Stadium is scheduled for 8:15 p.m. ET; the game will be broadcast on Apple TV+.
The Diamondbacks and Cardinals will open up a three-game series Friday when Zac Gallen (5.14 ERA, 56 IP) takes on Miles Mikolas (3.77 ERA, 39 1/3 IP). Both teams are in the thick of the NL Wild Card race and enter this matchup on respective two-game losing skids.
Find my Diamondbacks vs Cardinals prediction below, plus same-game parlay picks for Friday night.
Diamondbacks vs Cardinals Predictions, Parlay Picks
- Miles Mikolas Over 2.5 Earned Runs Allowed
- Miles Mikolas Under 15.5 Outs Recorded
- Diamondbacks -1.5
Diamondbacks vs Cardinals Parlay Odds: +268 (DraftKings)
This looks like a good spot to try and target Mikolas having a really ugly outing versus a deep Diamondbacks lineup that has torched right-handed starters this season. They have shown strong plate discipline and should be able to get Mikolas out of the game fairly early, particularly in game scripts that involve him allowing three earned runs.
There is a decent chance Zac Gallen does not fare overly well in this matchup, adding the Diamondbacks to cover the run-line takes this parlay from +130 to +266, which is enough of a difference for me to believe it is worth adding given that we are targeting a disastrous outing from Mikolas.
Diamondbacks vs Cardinals Odds
| Diamondbacks Odds | ||
|---|---|---|
| Run Line | Over/Under | Moneyline |
-1.5 +150 | 8 -115o / -105u | -110 |
| Cardinals Odds | ||
|---|---|---|
| Run Line | Over/Under | Moneyline |
+1.5 -178 | 8 -115o / -105u | -110 |
Diamondbacks vs Cardinals Projected Starting Pitchers
| RHP Zac Gallen (ARI) | Stat | RHP Miles Mikolas (STL) |
|---|---|---|
| 3-5 | W-L | 3-2 |
| 0.1 | fWAR (FanGraphs) | 0.8 |
| 5.14/4.16 | ERA /xERA | 3.77/4.45 |
| 4.68/4.15 | FIP / xFIP | 3.59/5.06 |
| 1.38 | WHIP | 1.21 |
| 14.0 | K-BB% | 6.3 |
| 37.3 | GB% | 37.2 |
| 91 | Stuff+ | 88 |
| 104 | Location+ | 106 |
Diamondbacks vs Cardinals Preview, Prediction
Diamondbacks Betting Preview: Gallen Aims to Deliver
It's been a very disappointing start to the season for Zac Gallen, who was the Opening Day starter for a Diamondbacks rotation that was expected to post better results this season compared to 2024.
Arizona's starting rotation has been a disappointment with a 4.25 ERA through 50 games, and Gallen's slow start has been a big part of the problem.
Gallen holds a 4.16 xERA and 4.15 xFIP. Based on those two statistics and his historical results, he will likely trend in the right direction moving forward, but it still appears as though he is far from the pitcher he once was. He has been hard hit 44.3% of the time, and holds a career-worst K-BB% of 14.0.
Pitch metrics suggest Gallen has regressed year over year, as he holds a Stuff+ rating of 91 and a Pitching+ rating of 99.
In a small sample of 18 2/3 innings, Gallen has been much more effective pitching on the road compared to batter-friendly Chase Field — he holds an ERA of 3.38 and a 0.91 WHIP in 18 2/3 IP on the road.
Arizona's bullpen has also been a concern, as it has allowed an ERA of 5.28 and an xFIP of 4.09.
Offensively, the Diamondbacks have been highly effective once again, after finishing the 2024 campaign ranked third in wRC+ and first in runs scored per game. They currently rank fourth in wRC+, first in BB/K ratio, and fourth in hard-hit rate. They have enjoyed playing at full health recently with zero everyday position players on the IL, and have hit to a wRC+ of 130 over the last two weeks.
Arizona has been particularly effective versus right-handed pitchers, as it holds a wRC+ of 123.
Cardinals Betting Preview: Mikolas in Poor Form
Miles Mikolas struggled mightily in 2024, pitching to a 5.35 ERA across 171 2/3 innings, but he has enjoyed a nice bounce back early on this season.
His xERA of 4.45 and xFIP of 5.06 do suggest he is still likely to trend towards below-average results moving forward, however, and his Stuff+ rating of 88 and Pitching+ rating of 92 suggest he has not improved compared to last season.
Mikolas has been hard-hit 42.5% of the time and holds a K-BB% of 6.3. He has allowed just 0.40 HR/9, which is the best mark of his career by a wide margin, and stranded 68.3% of base runners.
The Cardinals also have no everyday position players on the IL and are in good form offensively, having hit to a wRC+ rating of 109 over the last 14 days.
They hold the fifth-best wRC+ in the league versus RHP, and hold a wRC+ of 125 at home this season.
Diamondbacks vs Cardinals Over/Under Prediction
Friday's series opener seems likely to feature some fireworks offensively, as both offenses have been in good form and have been highly effective versus right-handed pitchers this season.
Gallen does appear to be a candidate for positive regression moving forward, but he still looks likely to be close to a league-average starter this season, and is backed by an Arizona bullpen that has not been effective.
Mikolas looks to be a pure fade candidate entering this matchup — many of his underlying metrics suggest he's close to the same pitcher that held a 5.35 across a hefty sample of innings in 2024.
Busch Stadium plays as a league-average park in terms of run creation, and should hold fairly neutral conditions for run production Friday as first pitch calls for 69 degree temperatures and essentially no wind.
At -130 or better there looks to be value betting this matchup to feature over 8.5 total runs, as both teams appear to be well situated to continue their strong recent production at the plate.
Pick: Over 8.5 Runs -120 (Bet365, Play to -130)
Moneyline
At a price of -130 my lean would be with the Diamondbacks in this matchup, as Gallen still appears to offer an edge over Mikolas, and Arizona's offense has been dominant of late, which is no surprise given its form over the last two seasons.
Run Line (Spread)
Betting the Diamondbacks to cover the run-line at +132 would be my first choice in terms of backing the run-line, and if prices in the +140 range became available that would be worthy of a bet.
Over/Under
As outlined, betting the game to feature over 8.5 runs is my favorite play from this matchup.
