• 2.1 baseline — his last 10 games; only 3 this season, too few to blend
• −0.1 opponent leak — they concede 89.3/game vs a 93.4 league average
• +0.8 at this ground — averages 2.9 there (14 gm)
• vs them: averages 2.0 over 2 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.