Comparing the Phillies’ and Giants’ Rotations

On Twitter, @TheBaseballChik asks:

Better 4-man rotation, Giants or Phillies?

Let’s take a look using SIERA over the last three years. Click on the charts to view a much larger version.

What you should be noticing is a lot of red leaning towards the left side of the graph. If not for Tim Lincecum, the Phillies would currently own the four-best starting pitchers in each of the 2008, ’09, and ’10 seasons among the eight pitchers in question. (Note that Madison Bumgarner was a rookie last year, but even still, he was the seventh best out of eight.)

Of the big four, the only significant regression we can expect out of the Phillies’ four pitchers would be from Roy Oswalt. Near the end of December, I analyzed the starters and concluded:

Oswalt, on the other hand, did have a bit of a lucky 2010 season. His 2.76 ERA was separated from his 3.33 SIERA because of a .261 BABIP and a 78 percent strand rate. Over his career (spanning over 2,000 innings), however, he has shown some legitimate ability to strand runners as his career average lies at 76 percent. Halladay, by comparison, has a 73 percent strand rate — much closer to the league average which tends to reside in the 70-72 percent range.

Since we’re using mostly-luck-neutral statistics, though, Oswalt still grades out well among the eight pitchers in question.

On the Giants’ end of things, there is no question that Tim Lincecum is one of the top-two starters along with Roy Halladay. However, Matt Cain may be one of the most overrated pitchers in baseball (though you can’t fault him for pitching to the strengths of his home ballpark**) and Jonathan Sanchez‘s enormously high walk rate sabotages the benefits of his high strikeout rate. Consider that both Sanchez and Cole Hamels had a K/9 above 9.0 in 2010 (Sanchez 9.5, Hamels 9.1) but Hamels walked nearly half as many batters (Sanchez 4.5 BB/9, Hamels 2.6). Bumgarner has promise but will need to bolster his K/9 well into the 7.0 territory and keep his BB/9 in the low 2’s.

** (Joe Posnanski-esque aside) Many have been insistent on docking players like Matt Holliday and Carlos Gonzalez points in MVP award voting for having divergent home/road splits. Why don’t we do the same for pitchers? Matt Cain is widely regarded as among the best in the game, but he’s a fly ball pitcher (45 percent career average) in a very spacious ballpark (home run park factor of 82 per Cain has a career home ERA of 3.19 with a 4.47 xFIP and a career road ERA of 3.76 with a 4.39 xFIP. AT&T Park has been very good to Cain.

For what it’s worth, Matthew Pouliot ranked all 30 Major League teams’ starting rotations and the Phillies’ came out on top by an overwhelming margin.

The question that @TheBaseballChik posed is interesting, especially when we’re all dying for some baseball, but there is really no debate.