True but there’s articles out there that analyze the performance of any player that leaves Colorado and their numbers in general do not change very much. What would be at least as telling to me is: Has any player ever left Colorado and had their numbers improve? Galarraga had his numbers jump significantly at age 32 - especially over his previous 4 seasons - once he hit Colorado - now he did have pretty similar numbers his first year in Atlanta as well. As long as you are accounting/equalizing for the fact that everyone hits better, in general, at Coors, GMs probably won't go too far wrong. I'd assume some hitters will do slightly better at Coors than others: hitters that feast on fastballs (because high-spin pitches are much less effective at Coors), power-hitters with extremely high average launch angles (because duh), and high OBP guys with very low launch angles (because the ball just travels farther, and the outfield is massive). But focusing on "stars" and how they have fared since leaving Coors seems a weird way to evaluate the post-Coors effect. Most everyone that becomes a "star" and signs somewhere else tends to be over-valued and likely to underpreform most peoples' expectations.