• 0.7 baseline — 0.6 × season 0.8 (12 gm) + 0.4 × last 10 0.7
• −0.0 opponent leak — they concede 34.1/game vs a 35.7 league average
• −0.4 at this ground — averages 0.3 there (6 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.