• 0.2 baseline — 0.6 × season 0.2 (18 gm) + 0.4 × last 10 0.3
• −0.0 opponent leak — they concede 9.6/game vs a 12.2 league average
• −0.1 at this ground — averages 0.2 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. Round 19: 2 — far outside his usual range; kept in the average, not smoothed away.