• 10.2 baseline — 0.6 × season 10.5 (8 gm) + 0.4 × last 10 9.8
• −0.4 opponent leak — they concede 353.4/game vs a 369 league average
• −0.2 at this ground — averages 10 there (14 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.