Purdy
QB · SF vs DEN
Proj pts
16.9pts
market
Nix
QB · DEN vs SF
Proj pts
16.6pts
market
Bo Nix or Brock Purdy: who should I start in Week 4?
Start Brock Purdy. Bench Bo Nix. Brock Purdy leads at 16.9. Bo Nix is the first one out, 0.3 short.
Crowd: started Purdy 85% · Nix 47%
Highlights
Pros
- Spike upside31.1 ceiling
Cons
- Tough matchupTough · D vs QB
- Shaky floor11.9 floor
Some recent form, opportunity and matchup figures still lean on the 2025 season (not enough games played this season yet).
Week 4 · Updated Tue 6:00 AM ET
Why Brock Purdy
Start Brock Purdy — projects 16.9, a tough matchup vs DEN, with a rising role.
Brock Purdy projects 16.9 points on a 11.9–31.1 range. The matchup grades as tough against DEN. Usage: pass attempts / game at 31.6. Net: Brock Purdy is start this week.
Working for Purdy: Spike upside (31.1 ceiling).
Working against Purdy: Tough matchup (Tough · D vs QB), Shaky floor (11.9 floor).
Where Purdy leads the head-to-head: Projection (16.9 vs 16.6); Ceiling (31.1 vs 22.5); Implied team total (25.3 vs 22.3); Last 3 avg (27.0 vs 14.6); Last 5 avg (24.6 vs 14.7); vs season (+2.2 vs -1.8); Boom rate (22% vs 12%); Yards per attempt (7.6 vs 6.4); Touchdown rate (7% vs 4%); Implied total (25.3 vs 22.3).
Why Bo Nix
Sit Bo Nix — projects 16.6, an even matchup vs SF, but the role is cooling.
Bo Nix projects 16.6 points on a 13.7–22.5 range. The matchup grades as neutral against SF. Usage: pass attempts / game at 36.0. Net: Bo Nix is a bench this week.
Where Nix leads the head-to-head: Floor (13.7 vs 11.9); Pass attempts (36.0 vs 31.6); Matchup grade (recency weighted) (B- vs D); Consistency (54% vs 51%); Bust rate (12% vs 22%); Pass attempts / game (36.0 vs 31.6); Completions / game (22.8 vs 21.9); Rush attempts / game (4.9 vs 3.7); Rush yards / game (20.9 vs 16.3); Rushing production share (21% vs 18%); Grade vs QB (recency weighted) (B- vs D).
Recent form
Brock Purdy's last 5 games: PPR points 36.9, 5.2, 21.1, 28.5, 31.3 (oldest to newest).
Bo Nix's last 5 games: PPR points 19.5, 10.5, 5.4, 14.1, 24.1 (oldest to newest).
Purdy has already beaten Nix's 16.6 projection in 4 of his 5; Nix has beaten Purdy's 16.9 in 2 of his 5.
At least 1 of these 5 were played before the 2026 season — the card does not date them.
Matchup
Brock Purdy (SF) faces DEN, kickoff Sun 4:25 PM ET. The matchup is rated tough. Betting line: implied team total 25.3, spread -3.0.
Bo Nix (DEN) faces SF, kickoff Sun 4:25 PM ET. The matchup is rated neutral. Betting line: implied team total 22.3, spread +3.0.
What flips it
Purdy's edge is 0.3 points (16.9 to 16.6). Nix's ceiling (22.5) clears Purdy's projection, so a big game from Nix flips it. Purdy's floor (11.9) sits under Nix's projection, so a quiet game from Purdy flips it too. Confidence in the call: lower.
How to read these numbers
- Confidence in the call
- How clear-cut this start/sit call is — how decisively the player beats the alternative he competes with (for a starter, the best player on your bench; for a bench player, the last one in your lineup), on both projected points and the overlap of their likely ranges. A clear play reads high; a genuine toss-up reads lower. It rates the decision, not the player’s own volatility, and is not a measured accuracy rate.
- Floor
- The 20th percentile of the same simulated distribution.
- Ceiling
- The 90th percentile of the same simulated distribution.
- Matchup grade
- The opponent’s points allowed to this position per game, weighted toward recent games, then graded on a curve across the 32 defenses.
- Implied team total
- The points the betting market expects this team to score, derived from the game total and the spread. Market-derived, not modelled by Nuvela.
- Trend
- The direction of his scoring across the trailing window, classified as heating, steady or cooling.
- Consistency
- The share of his games that landed within a set band of his own per-game average.
- Boom rate
- The share of his games that finished inside the top 12 scorers at his position for that week.
- Bust rate
- The share of his games that came in under half of what he was projected for that week.
- Defense funnel
- Whether the opponent’s rush defense and pass defense are far enough apart to push offenses one way. A gap inside the band reads Neutral.
- Game script projection
- The expected state of the game for his team — favoured, level or trailing — taken from the closing spread.
More start/sit comparisons from this week's PPR projections. Open a pair for the call and the reasoning.