with any prospect, people will be all across the board. but I would say scouts are wrong more often the right. That is why they thought Hansen would dominate. Why they said Lowrie couldnt hit ML pitching or field the position, why Seattle gave up on a prospect named Varitek because he couldnt hit or catch well enough to be considered a ML starting catcher, etc, etc...
as for the trends of highschoolers... last year, 16 of the 30 were HS. the year before, 14 of the 30. The HS's are picked early and often because of the 'potential'. And as for the numbers fluctuating, it is important also to note that HS's scare off a bunch of teams because they actually have leverage in terms of demanding bonuses because they can always go back to school. So a bunch of higher rated guys slip out of the first round due to bonus demands, not because scouts place their skill level lower.
but the fact is the guy has dominated in the league he was in.
his fastball has very very good late movement (thus the speed doesnt matter as much. If you throw it 95 but it is straight MLB hitters will hit it, if you throw 92 with movement, they wont.)
At 22, he is a more advanced prospect then kids in the draft, he has a more impressive track record etc...He will likely be ranked as the number 2 pitcher in our system, behind only Bowden. Bard and Hagadone are the next best pitchers, but Hagadone is returning from TJ surgery and Bard is a late inning reliever only. A pitcher who has #3 potential is higher ranked. (I guess we will see, if they sign him, what Soxprospects puts him at).
Ultimately, I am not expecting an Ace out of him, but I think he represents a creative way for the team to go get a kid who would be a top prospect really for significantly less then it would cost them if he were a top draft pick.
Edit:
The sox have been scouting him for over a year (
http://www.boston.com/sports/baseball/redsox/extras/extra_bases/). Their scouting department regarding pitching has been pretty [dang] good lately (some exceptions, Hansen, etc...).
Additionally, the fact that he already possesses three pitches is huge.