MLB Baseball Analytics - Baseball Analytics Blog

Take a look at the AL East standings on April 19 and the Red Sox results since.

On April 19:

April 19 - May 15, 2013:

Nobody could have expected the Sox to have maintained their torrid start, so a regression was expected and occurred.

Let's examine some reasons for the Sox return to Earth

The Red Sox team ERA through April 19 was 2.69; since, 4.82.
Starters ERA through April 19 was 2.23; since, 4.67.
Relievers ERA through April 19 was 3.43; since, 5.16.

Take a look at some individual differences

The Sox are heavily reliant upon their top three starters in their rotation and they have regressed:

Up to April 19, Clay Buchholz had a 0.41 ERA, after, a still very good, 2.45
Up to April 19, Jon Lester had a 1.73 ERA, after a fair, 3.71
Up to April 19, Ryan Dempster had a 2.65 ERA, after, a very shaky, 4.35

The Bullpen

Their bullpen has been hit with a season-ending injury to Joel Hanrahan and a DL-inducing injury to Andrew Bailey.

However:

Up to April 19, Junichi Tazawa had a 1.12 ERA, after, a not very good, 5.40
Up to April 19, Koji Uehara had a 0.00 ERA, after, a not very good, 4.50

Let's move to the offense, which has improved

Up to April 19, the team was hitting .257, with an OBP of .333, and slugging .411.
Since April 19, the team is hitting .270, with an OBP of .345, and slugging .459.

The individual batting averages have been a mixed bag before and after April 19

The always hard playing Dustin Pedroia was hitting .310 up to April 19 and .355 since then.
Jarrod Saltalamacchia has also improved hitting .231 up to April 19 and .286 since then.
Stephen Drew has found his stroke jumping from .087 to .278.
Daniel Nava has fallen going from .333 up to April 19 and .265 since then.
Similarly, Shane Victorino has gone from .322 up to April 19 and .269 since then.
Mike Napoli has remained consistent .262/.261.
However, Will Middlebrooks, Jonny Gomes and David Ross still are not hitting well.

So, where's the rub?

Up to April 19, the team was hitting .305 with runners in scoring position.
Since April 19, the team is hitting .255 w/RISP.

With runners in scoring position both Dustin Pedroia and Daniel Nava have been consistently good with numbers over .300 before and after April 19.
Since April 19, Stephen Drew has gone from .000 to .368 w/RISP and Jonny Gomes has gone from .000 to .286.
But it has hurt that the red-hot Mike Napoli has dropped from .333 to .258 since April 19.
Jacoby Ellsbury has gone from .400 to .118 since April 19.
And Saltalamacchia and Middlebrooks have both been ineffective all season long with runners in scoring position.

Perhaps you are wondering why I chose April 19th as my cutoff date

You see, on April 20 David Ortiz made his season's debut.

And while you certainly can't complain about Big Papi's .329 average with five homers and 20 RBI or his .321 average w/RISP, you do have to wonder if the team let down after his return or it was simply an expected regression to the mean.

We'll learn a ot more about this team over the next 25 games.