Willingham only had 5 HR's where his actual distance was greater than his true distance. All the rest, his ball landed shorter than his true distance. For a net difference of 95 feet, or 2. 7 feet per home run. At Target Field, he underhit his true distance by 98 feet, or about 3 feet per HR. His HR/FB rate may still come down but I am skeptical that we can yet say how much outside factors are contributing to his luck, esp. least at Target Field. It is still new and the local 9 have only fielded 2 true power hitters in its existence. Maybe as the sample grows, we won't see such gaps between actual distance and true distance for players like him. Out of curiosity, I looked up at the weather on May 30, 2012 in Minneapolis. This was the date when Willihammer hit a HR with the greatest net outside impact - 9 due to wind, -3 due to temp, and 3 due to altimeter. As you can see, he hit the ball almost due north: ESPN Home Run Tracker :: Player and Field Detail Yet the weather on that day was this? History | Weather Underground