SF vs ARI prediction for May 20, 2026: Our Monte Carlo simulation ran 10,000 game iterations and projects ARI 4.2 - SF 4.8. SF is favored with a 54.4% win probability. The run line is -1.5 and the total is 8.5. Model projects 9.1 total runs.
ARI
4.2
Projected Score
VS
O/U 8.5
SF
4.8
Projected Score
Win Probability
ARISF
-1.5
Run Line (ARI)
8.5
Total Line
10,000
Simulations
Calibrated accuracy at this confidence: 51.3% (2,197 games)
Projected Runs Range 10th – 90th percentile
SF
357
ARI
246
Pick Results
Merrill Kelly OVER 4.5 Ksk_propsLOSS-1.00u
Starting Pitcher Matchup
Tyler Mahle R
SF
FF47%92 mph19% whiff
FS25%85 mph26% whiff
FC16%88 mph9% whiff
Merrill Kelly R
ARI
CH28%88 mph31% whiff
FF26%92 mph15% whiff
FC15%91 mph14% whiff
Weather Impact
Chase Field
91°F8 mph windRoof: retractable
HR: 1.057 Total: 1.028
thin air
Bullpen Comparison
SF
3.44ERA
4.14FIP
7.75K/9
4.79BB/9
1.33WHIP
ARI
3.43ERA
3.61FIP
8.16K/9
2.58BB/9
1.04WHIP
Betting Edges
RUN_LINE AWAY +1.5
-30.3% EV
-192
F5_ML HOME
-21.3% EV
-135
RUN_LINE HOME -1.5
-18.6% EV
+160
ML HOME
-16.7% EV
-132
F5_ML AWAY
+14.0% EV
+108
ML AWAY
+11.6% EV
+112
First 5 Innings & NRFI
SF F5
3.1 runs
50.2% win
ARI F5
2.5 runs
36.4% win
F5 Total
5.6
NRFI
49.7%
YRFI
50.3%
Avg 1st Inn Runs
1.08
HR Spotlight
Avg HRs
3.3
Over 0.5 HR
96%
Over 1.5 HR
84%
No HR
4%
Casey Schmitt SF30.0%
ISO: 0.264 | Barrel: 12.8% | vs Merrill Kelly | Park: 1.06x
Adrian Del Castillo ARI26.2%
ISO: 0.158 | Barrel: 6.8% | vs Tyler Mahle | Park: 1.06x Platoon: 1.12x
Luis Arraez SF25.2%
ISO: 0.084 | Barrel: 5.2% | vs Merrill Kelly | Park: 1.06x Platoon: 1.12x
Pitcher Strikeout Projections
Tyler Mahle
0.0 K projected
SF | K/9: 0.0
Merrill Kelly
0.0 K projected
ARI | K/9: 0.0
Injury Report
SF8 injured
Reiver Sanmartin RP60-DAY-IL
Jung Hoo Lee RFDAY-TO-DAY
Logan Webb SP15-DAY-IL
Heliot Ramos LF10-DAY-IL
Jason Foley RP60-DAY-IL
Jared Oliva CF60-DAY-IL
+2 more
ARI8 injured
Corbin Burnes SP60-DAY-IL
James McCann C10-DAY-IL
A.J. Puk RP60-DAY-IL
Jordan Lawlar LF60-DAY-IL
Pavin Smith 1B60-DAY-IL
Carlos Santana 1B10-DAY-IL
+2 more
Edge Analysis
Moneyline
SF 54.4%
-18.6 pts
Run Line
-1.5
-18.6 pts
Total
8.5
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How this prediction was generated: This page shows output from the Olympus Bets MLB Baseball Monte Carlo engine. Each game is simulated 10,000 times using real-time team data, injury reports, and current odds. Probabilities are calibrated using Bayesian methods and sized via the Kelly Criterion. Full methodology →