• 0.2 baseline — his last 10 games; only 3 this season, too few to blend
• −0.0 opponent leak — they concede 7.8/game vs a 9.4 league average
• +0.3 at this ground — averages 0.5 there (31 gm)
• vs them: averages 0.5 over 8 games — evidence, never summed

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.