Today’s point is that you have better results as a starting pitcher in games when you don’t allow a home run. Really it is.

You probably would have guessed that’s the case. What you might not have guessed is how dramatic the difference can be. Here, for example, are the differences in results for the three Phillies pitchers who have made more than 10 starts this season in games when they have and have not allowed at least one home run in a game:

 
Starts where he allowed at least 1 HR in game

Starts where he allowed 0 HR in game
  Team
record
ERA Ratio Team
Record
ERA Ratio
Hamels 3-5 5.73 1.50 4-2 2.92 1.30
Blanton 4-7 5.76 1.45 3-0 2.50 1.33
Moyer 5-6 7.56 1.68 3-1 2.52 1.12

The Phils are 22-21 in the games started by the trio — 10-3 in the 13 games where they didn’t allow a home run and 12-18 in the 30 where they did.

Here are the numbers for the three combined when they have and have not allowed at least one home run in a start for the season:


IP

ER

H

BB

SO

ERA

Ratio

Allowed HR

175.3

119

216

43

137

6.11

1.48

Didn’t allow HR

80

24

78

22

66

2.70

1.25

In the case of those three so far this year, they’ve struck hitters out at a better rate and prevented hits at a much better rate in the starts where they’ve allowed a home run. What’s a little curious to me is that they’ve walked hitters at a higher rate as a group in the starts where they did not allow a home run than the starts where they did. In the starts where they didn’t allow a home run they walked 22 in 80 innings or 2.47 per nine innings. In the starts where they did allow at least one homer they walked 2.21 per nine. Both Hamels and Blanton walked have walked more batters in their games this season when they didn’t allow a home run than in their games where they did.

It’s obviously a tiny amount of data, but, also curiously, Hamels also issued more walks in his starts in 2008 when he didn’t allow a home run. Here:


Hamels ’08
  IP ERA Ratio BB/9
Starts
allowed HR
123.7 4.37 1.18 1.75
No HR 103.7 1.56 0.96 2.52

The numbers are way better overall in the non-home run starts, but he walked more batters per nine innings. Since his ratio was so much lower in the non-home run starts you can probably guess that he allowed a lot fewer hits. He did — 6.16 hits per nine in starts when he didn’t allow a home run and 8.88 hits per nine in starts he did.

Blanton is the other guy of the trio who is walking more guys this season in his starts when he doesn’t allow a home run. He’s had kind of a brutal transition from Oakland. In 2008, between his starts for Oakland and Philly he allowed 22 home runs in 197 2/3 innings. So far in ’09 he’s allowed 17 in 83 2/3 innings. His numbers weren’t as dramatic as Hamels’ for last year, but he did walk batters at a slightly higher rate in his starts when he did not allow a home run:


Blanton ’08
  IP ERA Ratio BB/9
Starts
allowed HR
112 5.06 1.38 2.97
No HR 85.7 4.20 1.42 3.05

This says that Happ will start tomorrow, Ibanez and Eyre are rehabbing and that Lopez, Carrasco or Carpenter could start on Friday against the Mets.