• 1.0 baseline — his last 5 games; only 3 this season, too few to blend
• −0.1 opponent leak — they concede 8.5/game vs a 9.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing

Derived, not measured — plain arithmetic over his real games, shown in full. Adjustments can overlap (a game at this ground can also be a wet one); they add simply, and this note is the admission.