• 4.5 baseline — 0.6 × season 4.5 (4 gm) + 0.4 × last 4 4.5
• −0.1 opponent leak — they concede 152.3/game vs a 155.4 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing

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.