Scott Baker vs Randy Wolf
One thing that jumped out at me as I perused Light Rail's B-R page was his strikeout rate: 8.6 K/9. What? It did increase from 7.3 in 2009 to 7.8 in 2010, but I wasn't expecting another 0.8 jump. However, the season is just shy of 50% complete and so, how much of the increase is real? Fortunately, that was recently answered.
What we want is the K/(PA-IBB-HBP)* line, and that says at 126 denominator units, 50% is the player's ability and 50% is the mean. Baker has 369 PAs, which means 74.5% of the 8.6 K/9 is him while the other 25.5% would be regression to the mean. The mean we want would be Baker's historical performance with however much regression is needed.
Taking the last three years, Baker has 2240 PAs, which means we need 94.7% of those three years and 5.3% league average. Baker's three year average for those three years is 7.5 K/9, which is reasonably close to the league average of 6.8. Let's just use 100% Baker. More rounding error.
Putting it all together means the best estimate for his talent right now is 8.3 K/9. Combined with the miniscule (0.09) increase in his BB/9 rate equals good things for his results. His xFIP so far is easily his best yet and his FIP is slightly better than from 2008. Finally, an ace!
* I'm calling these PAs from now on, despite it actually not being a plate appearance. He has one intentional walk and four hit batters, so it's basically rounding error anyway.