• 1.5 baseline — his last 10 games; only 1 this season, too few to blend
• −0.1 opponent leak — they concede 51/game vs a 56.6 league average
• −0.3 at this ground — averages 1.2 there (18 gm)
• vs them: averages 0.0 over 1 game — 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.