• 3.1 baseline — his last 10 games; only 2 this season, too few to blend
• +0.5 opponent leak — they concede 108.9/game vs a 93.4 league average
• −0.1 at this ground — averages 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.