• 5.0 baseline — 0.6 × season 5.0 (19 gm) + 0.4 × last 10 5.0
• +1.3 opponent leak — they concede 117.8/game vs a 93.4 league average
• −2.2 at this ground — averages 2.8 there (5 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.