• 6.5 baseline — 0.6 × season 6.6 (7 gm) + 0.4 × last 10 6.5
• −0.5 opponent leak — they concede 343.2/game vs a 369 league average
• −2.0 at this ground — averages 4.5 there (4 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.