There are a lot of good reasons not to believe in Ryan Vogelsong. It takes a five-minute perusal of his baseball-reference page to remind yourself that, oh yeah, the guy had a career ERA of nearly 6 coming into this year. In most years, he wasn't good enough to crack the rotation of the Pirates for the whole year.
So it's easy to be a little skeptical of the fact that, at the moment, Ryan Vogelsong has an ERA of 2.36 and the Giants are undefeated in his starts. We remember, after all, the legend of Ryan Sadowski, who fooled a lot of people into thinking the Giants might have found a diamond in the rough to shore up the back of the rotation. It turned out that, no, Sadowski wasn't any better than his minor league numbers and the fact that he was putting up a good ERA despite mediocre peripherals through 4 starts wasn't proof that he was an outlier.
The trouble with this comparison, though, is that Ryan Vogelsong's success this year is not tied entirely to wins and ERA. He's striking batters out at a clip of over 8 per 9. He's limiting walks. If you cover up the name next to the pitching line, it looks downright respectable.
I don't know if there's some reason to explain why Vogelsong is pitching so differently from what one would expect this year, given the rest of his career to date. Furthermore, it really is still a small sample size - 6 games and 4 starts in all - and it's completely within the realm of possibility that he'll revert to pitching like Ryan Vogelsong at some point in the future.
However, it's hard to deny that it's pretty darn cool that he's doing what he is so far. He's a good story, he seems like a great guy and he's pitching undeniably well no matter how you look at it. Let's just enjoy it.
Ryan Vogelsong: Dude Throws Complete Game Shutouts