• 1.0 baseline — his last 5 games; only 3 this season, too few to blend
• −0.0 opponent leak — they concede 11.8/game vs a 12.2 league average
• +0.3 at this ground — averages 1.3 there (4 gm)

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.