I have a feeling I'm entering into an intellectual quagmire by engaging you in a conversation as ridiculous as this. But I'll try.
First of all, your comparison of Sheen to Bautista is asinine. I have never claimed that Bautista is on steroids so I really don't know why you would bring him into the conversation. If you can come somewhat close to convincing me that Bautista is anywhere close to being relevant to this conversation I might respond. Otherwise, just drop the Bautista thing entirely. I'm not Cuban32 and I do not intend to engage you in a pages-long argument that goes nowhere.
As for Sheen, no it is not impossible for steroids to increase the velocity on one's fastball, but it is very unlikely that steroids are responsible for adding 6mph in 6-8 weeks to Sheen's fastball. First of all, the only way steroids are going to put velocity on a fastball is by strengthening the pitcher's legs and lower back, and even then this tends to allow a pitcher to throw longer at the same speed more so than it allows them to throw harder overall.
I've never seen a healthy pitcher, EVER, add 6mph to their fastball in 6-8 weeks simply from gaining strength. It happens due to fixing a major mechanical flaw, recovering from injury or working back into throwing shape after the offseason.
My point is that what Sheen attributes to steroids is probably just him regaining his motion and arm strength naturally. If steroids were really capable of that kind of addition in velocity, Roger Clemens wouldn't have seen his velocity steadily dip as he grew older. It would have at least stayed the same, if not gone up, if this was true.
At the time when he allegedly started using steroids, Clemens was still throwing mid to high 90's on a regular basis. Why didn't he make the jump into a consistent triple-digit velocity. If it was as simple as taking steroids, EVERY pitcher would take them.
Look, Sheen was apparently a pretty decent player in high school and I don't think he was more than maybe 26 or 27 when he filmed Major League, so if he had the potential at one point to throw hard, then I could see how he was able to put that kind of velocity onto his fastball in such a short time. Think about it. If you could add 6mph to any Major League pitcher, they'd all be entirely different.
There is a huge difference between 85 and 91 and 97. You know when you see that kind of jump in velocity normally? Between the first and second or third week of Spring Training when pitchers are still working themselves into shape. That's all that Sheen did.