As a Clay Buchholz owner I’ve kind of been a little impatient with the Sox’s strategy of calling up every AAA pitcher who can’t be moulded, fired, glazed, fired, and glazed again. Other than reading a quick paragraph in one of my fantasy magazines, I had no idea who or what Justin Masterson was. And now I understand why he was ranked as the third-best prospect going into 2009: This guy is good.

The next Derek Lowe? That’s what I’m hearing people call Masterson. Let’s take a look at his minor-league stats and pedigree.

At 6′6″, 235, Masterson’s only twenty quarter-pounders heavier than Lowe, who’s also 6′6″. Justin celebrates his birthday on March 22. So just over three months ago he turned twenty-three. He was a second-round (seventy-first overall) pick in the 2006 entry draft, and he threw one season of college ‘ball at San Diego State before going pro.

Justin hasn’t dominated at any stop in the minors. Before his call up he was 1-3 with a 4.23 for AA-Portland, then 1-0 in one start for AAA-Pawtuckett. His AA stats didn’t hint at a guy who would come up and go 3-0: 38 IP, 37 hits, 37:16 K:BB.

Masterson’s complete minor-league line:

2006: A+ Lowell in the Penn League: 3-1, 0.85 ERA, 31 IP, 20 hits, 33:2 K:BB.
2007: A+ Lancaster: 8-5, 4.33 ERA, 95 IP, 103 hits, 56:22 K:BB.
2007: AA Portland: 4-3, 4.34 ERA, 58 IP, 49 hits, 59:18 K:BB.

Cumulative minor-league stats: 0.31 home runs/9 IP, 8.36 hits/9 IP, 2.32 BB/9 IP, 1.19 WHIP.

Masterson throws a heavy two-seam fastball from a 3/4 arm angle. He has a slider and change, but he throws the sinker. The sinker sits at 91-92, but can hit 94.

So far Masterson’s been great. His .168 OBA is terrific, and his 1.8 K:BB ratio is OK for a guy who had trouble throwing strikes in the minors. His OBA-allowed is .282, and his SLG-allowed is .364. Both good.

The question I have re: Masterson is whether his 3.73 pitches/batter is going to hold. He has a ton of strike outs for a guy who’s supposed to be pitching to contact. Brandon Webb’s pitches/plate appearance is 3.56. And that’s Brandon Webb. And Brandon Webb’s OBA-allowed is .281. And that’s Brandon Webb. The only difference is that Webb’s K:BB ratio is 3.28.

Masterson’s looked really good this year, and, other than Julio Lugo, the Sox have a terrific defensive infield. Still, you have to assume that he’s going to tack another two full runs onto that ERA as he makes his way through the league. His minor league numbers are tough to evaluate because you have to question how many hits were really hits (as opposed to balls that got past inferior defenders). But his BB/9 IP is going to get up to around 4.5-5, and that 1.06 WHIP is going to rise.

What to expect from Masterson: His ESPN player card lists him at 250, and he’s never thrown more than 150 innings in a season. So he’s guaranteed to wear down. As a long-term bet, I think he’s a great third starter. But his arm angle’s scary, and his inability to command his pitches (which is understanable at twenty-three) means he’ll probably be a couple-few years in developing.

I think there’s a good chance that, along the way, he loses his arm angle, loses movement on his sinker, and struggles to get back to a 4-ish ERA.