Divide and Conquer, NL East: Pitching Dominance

In last week's edition of Divide and Conquer, there was some controversy when Derek Lowe's name was brought up among the league leaders in WARP this season. This line of thinking got me examining the WARP totals for all of the division's finest pitchers. Dubious as the Lowe-for-WARP-leader campaign may be, it turns out (rather unsurprisingly) that the NL East as a whole is running out some of the best starting rotations in all of baseball, even when viewed through different lenses.
 

The NL East Starters
Here is how the NL East's five teams stack up in terms of three pitching statistics of interest: ERA, SIERA, and Baseball Prospectus's Fair Run Average (FRA), explained here. The five pitchers who have made the most starts for each team were selected and these are their results:

*FRA is scaled to match Run Average (RA), not ERA. To get an ERA scale, multiply the FRA value by 0.92.

As expected, these numbers compare favorably when judged against the rest of the divisions in the National League.

The NL East stands head and shoulders above the remaining divisions when evaluated as a whole. Among the NL East teams themselves, the worst rotations are those of Florida and New York, and both have injuries to blame for some of their prevailing problems; the Marlins have been without Josh Johnson for a month now and have had to deal with the horrors of early season Javier Vazquez, while the Mets have been without Johan Santana all season.

Of course Philadelphia and Atlanta lead the way in terms of pitching with two of the best staffs in baseball. The two teams are ranked first and second, respectively, in ERA and FRA, and they are not far apart in terms of SIERA. While it is difficult to argue that Atlanta's rotation can stack up with that of Philadelphia's, they do have a good argument among the teams vying for the position behind the Phillies, including the defending champion San Francisco Giants' rotation. Not only have Jair Jurrjens and Tommy Hanson been impressive, but Tim Hudson and Lowe have been as dependably solid as they were projected to be, and Brandon Beachy (3.21 ERA, 2.57 SIERA) has emerged as a legitimate top-of-rotation starter given his early work in the majors. Beachy's emergence is of particular interest because it was not assured that he would even receive a rotation spot before the season began, as he was competing with fellow prospect starter Mike Minor. It turns out that the Braves made the right decision to go with the strikeout-heavy pitcher that they did in Beachy (26.8 percent career minor league strikeout rate) over Minor (28.1 percent) despite their similar minor league stats and playing time.
 

My Best Five Versus Your Best Five
Looking at the division as a whole is interesting, but it does not have enough of a confrontational feel to it. What if each division had to pick its five best starters and use them on a team to compete? Would the NL East still have an edge when looking at only the best? Looking at the same pool of players as before, five of the best starters were selected to represent their respective divisions using two different criteria: SIERA and PECOTA-projected rest-of-season ERA.

First, the NL division teams selected via 2011 SIERA.

This set of five-man rotations coming from each division is pretty impressive, but the NL East's five-man crew has the edge. Despite each division's rotation having sub-3.00 SIERA pitchers leading the way, only the NL East's boasts four (!) pitchers below that mark, with the fifth rotation member being Tommy Hanson, a pitcher who would have ranked second in either of the other divisions' rotations. Also notable regarding the NL East's rotation is the names that are missing, including Florida's Anibal Sanchez (3.24 SIERA) and Josh Johnson (3.31) and Washington's Jordan Zimmermann (3.96), showing that the division has depth beyond the cities of Philadelphia and Atlanta.

In this selection method, the NL West seems to be able to put up a fight. Again, there are some noticeable absences in both the NL East and West lists, including Anibal Sanchez and Cole Hamels in the East and Chad Billingsley, Hiroki Kuroda, and Ubaldo Jimenez in the West. One major factor playing into this comparison is the presence of park factors changing the numbers involved. In the NL West, the non-San Francisco pitchers pitch in some of more favorable pitcher's parks in baseball, tilting their projections towards lower ERA marks. In the NL East rotation, the three Philadelphia starters have some of their numbers tilted towards higher ERA marks because of the presence of Citizen's Bank Park.

On the East side, we see Johnson and Oswalt replace Beachy and Hamels, but the results look similar as the East seems to be loaded with pitchers with sub-3.00 ERA talent. Johnson in particular has been derailed this season with injury but, before succumbing to shoulder inflammation, had a 1.67 ERA and a 1.5 WARP in just 60 1/3 innings pitched. He is slated to return in early August, but with the Marlins out of the running for anything of importance in 2011, perhaps it would be wise if the Fish saved their investment for another season.
 

Give Us Your Scraps
Of course, we knew the NL East was top-loaded with pitching talent, but what about the dregs of the division's rotations? Can the bottom feeders also maintain top-dog status among the National League's divisions? Looking at the same pool of players, here are the five worst starters in each division, measured by SIERA.

Among these poor 2011 performers, it does seem that the NL East has once again got the best of the deal. Having players like Livan Hernandez and John Lannan at the tail end of the productivity spectrum is a luxury the rest of the league does not have. In particular, the NL West has suffered through some pronounced difficulties in terms of the back end of their teams' rotations, even though the front end has been as strong as ever. The NL East rotations, however, boast the strongest back ends, especially given Dillon Gee's promising start in New York and Javier Vazquez's continued post-May resurgence.

It seems that the conventional wisdom of the NL East's rotational dominance seems to match the statistics from the first half of 2011. The division has an overall advantage, an advantage with their best pitchers, and an advantage with their worst pitchers.  It’s a good thing, too, because the teams of the NL East have needed that advantage to stay in the playoff picture; only one of the division's offenses is above average this season. Given their performance in terms of SIERA and PECOTA's projections, it seems that this sort of pitching dominance will continue as 2011 marches on. If the adage of “pitching wins championships” holds some water, then the playoff contenders in the NL East will have an edge.