bayesRatings

Giants at Diamondbacks

MLB · Monday, May 18 · 8:40 PM CT · Chase Field · Final SF 2 – ARI 12
← MLB / May 18

Final Box Score

from the game summary
Team123456789THE
SF011000000283
ARI4120500012160
Team box
SF·ARI
8
hits
16
1
home runs
2
1
walks
2
7
strikeouts
3
135
pitches thrown
132
3
errors
0
Top hitters
PlayerTeamH-ABRHRRBI
Nolan ArenadoARI1-4114
Gabriel MorenoARI2-5212
Ketel MarteARI2-4202
Ryan WaldschmidtARI3-3201
Willy AdamesSF1-1111
Tim TawaARI1-4002
Pitchers
PitcherTeamIPHERBBK
Robbie Ray (L)SF4.111921
Zac Gallen (W)ARI6.04215

For context, not in our forecast.

Game Flow

score margin
ARI +10
SF +10
123456789
largest lead: ARI 10 · SF 0lead changes: 0

For context, not in our forecast.

Final · our forecast was SF 47%, ARI 53% · Updated May 18

Expected margin
Even
Expected score
ARI 4.8 – 4.6 SF
Expected total
9.4
GiantsThe matchupDiamondbacks
+114Our fair odds−114
4.6Expected runs4.8
−0.05Power rating+0.00
3.5Runs / game4.4
4.3Allowed / game4.8
8.4Hits / game8.0
0.79Home runs / game0.89
2.1Walks drawn / game3.1
20−27Season record22−23
6−4Last 105−5

Prediction markets

Kalshi · Polymarket US · ProphetX · Novig
SF chance · ARI chance
Our model fair46.6%53.4%
Kalshi46.7%57.7%
Polymarket USno two-sided price
ProphetXno two-sided price
Novigno two-sided price
Full price table
TeamOur modelfairKalshipre-game · 8:40 PM CTPolymarket US ProphetX Novig 
Moneyline
SFSan Francisco Giants+11447%+11446.7%———
ARIArizona Diamondbacks−11453%−13757.7%———
Spreadabout even
SFSan Francisco Giants+0.2our margin————
ARIArizona Diamondbacks−0.2our margin————
Totalwe expect 9.4
Over9.4our total————
Under9.4our total————

These are each venue’s last prices before the start (Kalshi’s moneyline: its pre-game close). Odds are the price to buy that side now, taker fee included; the small percent is the implied chance of that same price. Highlighted is the best price in the row among venues on the same line. — means not listed (hover or tap for why). A market price is not the true chance of winning.

Margin range

Even game expected
San Francisco Giants by 13 runs: <1%San Francisco Giants by 12 runs: <1%San Francisco Giants by 11 runs: <1%San Francisco Giants by 10 runs: 1%San Francisco Giants by 9 runs: 1%San Francisco Giants by 8 runs: 2%San Francisco Giants by 7 runs: 2%San Francisco Giants by 6 runs: 3%San Francisco Giants by 5 runs: 4%San Francisco Giants by 4 runs: 5%San Francisco Giants by 3 runs: 7%San Francisco Giants by 2 runs: 9%San Francisco Giants by 1 run: 11%Arizona Diamondbacks by 1 run: 15%Arizona Diamondbacks by 2 runs: 10%Arizona Diamondbacks by 3 runs: 7%Arizona Diamondbacks by 4 runs: 6%Arizona Diamondbacks by 5 runs: 4%Arizona Diamondbacks by 6 runs: 3%Arizona Diamondbacks by 7 runs: 2%Arizona Diamondbacks by 8 runs: 2%Arizona Diamondbacks by 9 runs: 1%Arizona Diamondbacks by 10 runs: 1%Arizona Diamondbacks by 11 runs: 1%Arizona Diamondbacks by 12 runs: <1%Arizona Diamondbacks by 13 runs: <1%
← SF wins byARI wins by →
Arizona Diamondbacks wins by 2 or more38%
Arizona Diamondbacks wins by 3 or more28%
San Francisco Giants wins by 2 or more35%
Decided by one run27%

Centered on the expected margin above; shape from each team's expected runs, with ties after nine settled as one-run games, matched to 14,698 past MLB games.

Total range

9.4 expected
1 runs: 1%2 runs: 1%3 runs: 5%4 runs: 4%5 runs: 9%6 runs: 7%7 runs: 11%8 runs: 7%9 runs: 10%10 runs: 7%11 runs: 8%12 runs: 5%13 runs: 6%14 runs: 4%15 runs: 4%16 runs: 2%17 runs: 2%18 runs: 1%19 runs: 1%20 runs: 1%21 runs: 1%22 runs: <1%23 runs: <1%24 runs: <1%25 runs: <1%
Total runs, both teams
Total over 7.561%
Total over 9.543%
Total over 11.528%
Total from 8 to 1133%

Centered on the expected total above; shape from each team's expected runs, with ties after nine settled as one-run games, matched to 14,698 past MLB games.

Starting Pitchers

from the box score
SFRobbie Ray SP · last 3 starts: 17.0 IP, 3.71 ERA, 14 Kstarted
ARIZac Gallen SP · last 3 starts: 14.1 IP, 8.79 ERA, 12 Kstarted

Starting pitchers are part of our forecast.

Rest and Schedule

before this game
SF·ARI
May 17 at ATH
last game
May 17 at COL
0 days
days of rest
0 days
7
games in last 7 days
6
8th straight road game
home / road
home after a road game

For context, not in our forecast.

Team Comparison

2026 season · box-score averages from 45+ games
SF·ARI
−0.05
rating (0 = average)
+0.00
3.5
runs / game
4.4
4.3
runs allowed / game
4.8
20−27
season record
22−23
10−12
home record
12−9
10−15
away record
10−14
W2
streak
W1
6−4
last 10
5−5
8.4
hits / game
8.0
0.79
home runs / game
0.89
2.1
walks drawn / game
3.1
7.9
batter strikeouts / game
7.8
7.9
pitcher strikeouts / game
7.4
0.51
errors / game
0.49

Rating Trend

SF · ARI · 54 days
San Francisco GiantsArizona Diamondbacks
Rating (0 = average team)

Head to Head

last 10 meetings · ARI 5−5
Sep 17, 2025at ARISF 5 − 1
Sep 16, 2025at ARIARI 6 − 5
Sep 15, 2025at ARIARI 8 − 1
Sep 10, 2025at SFARI 5 − 3
Sep 9, 2025at SFSF 5 − 3
Sep 8, 2025at SFSF 11 − 5
Jul 3, 2025at ARISF 7 − 2
Jul 2, 2025at ARISF 6 − 5
Jul 1, 2025at ARIARI 8 − 2
Jun 30, 2025at ARIARI 4 − 2

SF · Last 10

6−4 · streak W2
May 17at ATH10 − 1W
May 16at ATH6 − 4W
May 15at ATH2 − 5L
May 14at LAD2 − 5L
May 13at LAD0 − 4L
May 12at LAD6 − 2W
May 11at LAD9 − 3W
May 10vs PIT7 − 6W
May 9vs PIT3 − 13L
May 8vs PIT5 − 2W

ARI · Last 10

5−5 · streak W1
May 17at COL8 − 6W
May 16at COL2 − 4L
May 15at COL9 − 1W
May 13at TEX5 − 6L
May 12at TEX4 − 7L
May 11at TEX1 − 0W
May 10vs NYM5 − 1W
May 9vs NYM2 − 1W
May 8vs NYM1 − 3L
May 7vs PIT2 − 4L