∅ Empty Set Football
Week 18 · 2026 regular season

San Francisco 49ers at Arizona Cardinals

Sun, Jan 10, 10:00 AM PT

Win probability
ESF
(win probability)
SF 80%
20% ARI

No betting line yet. Lines appear once books post them.

Unit matchups · entering week 18

Where each side has the edge

Each offense against the defense it faces, in CAP yards per attempt. Offense: higher is better. Defense (yards allowed): lower is better.

Pass: SF offense vs ARI defense
+1.401st
box score 8.4 · 2nd
Edge
SF
+0.7328th
box score 8.6 allowed · 32nd
Rush: SF offense vs ARI defense
+0.2011th
box score 4.6 · 8th
Edge
SF
+0.4627th
box score 4.4 allowed · 23rd
Pass: ARI offense vs SF defense
−0.6725th
box score 5.7 · 30th
Edge
SF
−0.459th
box score 6.1 allowed · 3rd
Rush: ARI offense vs SF defense
−0.3124th
box score 3.7 · 24th
Edge
SF
−0.367th
box score 3.7 allowed · 8th

CAP yards per attempt: yards per play relative to what the down, distance, field position and the specific opponent would predict; offense positive is good, defense (allowed) negative is good. Box score: yards per attempt as an official box score counts them, entering week 18.

CAP yards per attempt · 2026

How each matchup got here

Each unit's CAP yards per attempt entering each week. Offense: higher is better. Defense (yards allowed): lower is better. 0 is what the situation and opponent would predict.

SF pass offense vs ARI pass defense
SF pass offense ARI pass defense (allowed)
−0.3 0 +0.3 +0.5 +0.8 +1.0 +1.3 +1.5 +1.8 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 SF +1.40 ARI +1.00 −0.3 0 +0.3 +0.5 +0.8 +1.0 +1.3 +1.5 +1.8 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 SF +1.40 ARI +1.00
ARI pass offense vs SF pass defense
ARI pass offense SF pass defense (allowed)
−1.0 −0.8 −0.5 −0.3 0 +0.3 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 ARI −0.73 SF −0.45 −1.0 −0.8 −0.5 −0.3 0 +0.3 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 ARI −0.73 SF −0.45
SF rush offense vs ARI rush defense
SF rush offense ARI rush defense (allowed)
−0.3 0 +0.3 +0.5 +0.8 +1.0 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 SF +0.20 ARI +0.54 −0.3 0 +0.3 +0.5 +0.8 +1.0 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 SF +0.20 ARI +0.54
ARI rush offense vs SF rush defense
ARI rush offense SF rush defense (allowed)
−0.5 −0.3 0 +0.3 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 ARI −0.28 SF −0.36 −0.5 −0.3 0 +0.3 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6 ARI −0.28 SF −0.36
CAP win pct · 2026

How each team got here

CAP win pct entering each week. Higher is better; the league average is 0.50.

−0.25 0.00 0.25 0.50 avg 0.75 1.00 1.25 wk 1wk 2wk 3wk 4wk 5wk 6 SF 1.14 ARI −0.11 −0.25 0.00 0.25 0.50 avg 0.75 1.00 1.25 wk 1wk 2wk 3wk 4wk 5wk 6 SF 1.14 ARI −0.11
2026 results

Results so far

Each team's games before this one, with ESF's pre-game win probability for the team.

SF San Francisco 49ers

WeekOpponentResultESF win prob
pre-game, this team
1 @ LA Won 46%
2 vs MIA Won 77%
3 vs ARI Won 86%
4 vs DEN Won 60%
5 @ SEA Won 44%

ARI Arizona Cardinals

WeekOpponentResultESF win prob
pre-game, this team
1 @ LAC Won 16%
2 vs SEA Lost 19%
3 @ SF Lost 14%
4 @ NYG Lost 40%
5 vs DET Lost 34%
6 @ LA Won 21%
Week 18

Other games this week

Home team's chance to win before kickoff. Higher means the home team is more likely to win.

Dots: ESF model home win probability.

How to read this page

CAP win pct. A fading average of game scores with a half-life of 7 of the team's own games. A win scores 1 plus the opponent's win pct; a loss scores the opponent's win pct minus 1. Last season carries in. League average is 0.50; higher is better.

CAP yards per attempt. Yards per play relative to what the down, distance, field position and the specific opponent would predict. Offense: higher is better. Defense (yards allowed): lower is better.

Box score yards per attempt. Yards divided by attempts, counted the way an official box score counts them: rushing includes scrambles and kneel-downs; passing is gross yards per pass attempt, sacks excluded.

ESF win probability. A logistic regression on both teams' pre-game CAP win pct, with an intercept for home field.