What do you think about this pitching stat?

[Igetp2s]

Say a pitcher does much better against a lineup the 1st time through vs. the 2nd time around (or vice versa) in 2009. Do you think this trend is likely to continue in 2010, or is it simply a fluke and nothing should be drawn from those splits in 2010?

My guess is that there's a specific reason why a pitcher's performance would change considerably depending on 1st time through vs. 2nd time, whether better or worse, and is more likely to carryover. What do you guys think?

[Justin7]

What is the sample size?

New pitchers tend to do better the first time against a line up. Veterans can go either way.

[Thremp]

What is the sample size? New pitchers tend to do better the first time against a line up. Veterans can go either way.

Cite.

[Justin7]

Cite.

I don't remember where I read this... but new batters and new pitchers tend to do better at first until everyone figures out their weaknesses.

[benjy]

I don't remember where I read this... but new batters and new pitchers tend to do better at first until everyone figures out their weaknesses.

I read this about pitchers too - damn if I can recall where - and that it was 3 starts or so before scouting caught up with them, and hence do better when first promoted.

I've never read anything about batters, but anecdotally I've seen many hitters come up and do very well until a hole is spotted in their swing.

[Ruifgalmeida]

My opinion in the long run is going to be random, but i could be wrong

[Igetp2s]

I think I was unclear about what I meant. I wasn't talking about a rookie pitcher in his 1st time against a new team.

I was talking about within the same game, a pitcher's performance depending on how many times he's faced the same batters.

The sample size would be something like 30 starts X 9 AB's per lineup would be around 270.

Say in 2009, batters hit a combined .250 the 1st time through, .275 the 2nd time through, and .320 in their 3rd AB. How much of this trend would you think is simply randomness, and how much do you think is because of a specific part of a pitchers ability (i.e. he gets tired easily, loses velocity, loses command). It could just as easily go the other way (it takes him a couple of innings to settle in, but once he's gotten a few innings in he's much tougher).

[Justin7]

Ahh.

Generally, a pitcher does worse as his pitch count goes up. This isn't usually a factor in the first two run-throughs of the lineup, but the third, and especially the fourth time through, his ERA per at bat will go up.

[superjeff24]

it's not uncommon for average pitchers in the mlb to have higher batting averages against on the 2nd and 3rd times through a lineup. only top notch guys like Halladay who can pick apart your swing within one AB and have insane control are going to have lower and lower averages the 2nd and 3rd time through.

Also I personally wouldn't base my picks on this, as even a top notch pitcher can get lit up for 7 in the first 2 innings, dominate the rest of the game and take the L