The reason they use it in the minors is because it's in and out of your system rather quick and it yields decent gains. Don't you guys get tested for steroids at some point during the year by MLB ??Plus, the ballplayers are interested in the effect that it has on "fast-twitch" muscles.
I'll agree with you on the clearance time being a reason that athletes use winstrol but I disagree with you on the 'fast twitch' effect. I would say that the effect(s) on muscle fibres would be more of a function of training stimulus. Like training anaerobically for a higher percentage of fast twitch fibre muscle growth, and training aerobically for for higher percentage of slow twitch fiber muscle growth