(ed. note - "Doghouse is back with another installment of "Tuesday Nats Stats", Dave at Bottomfeeder Baseball checked in yesterday with a report entitled, "Milledge Takes Questions, Doesn't Know Riggo", from Lastings Milledge's Q&A at the ESPN Zone in DC, and last night's Game Report on the 1-0 DC loss to Philly can be found here.")

Last week we used BABIP to take a look at which Nats hitters were getting lucky with where their hits were falling.  With the exception of our two fresh-faced catchers, you'll recall that everyone was basically average or worse (even much worse for poor Kearns) in terms of lucky drops.  That may suck for team OPS right now, but it hints that things might get better when our hitters inevitably revert to the mean. And if Nick gets healthy.  Get well soon, Nick!

Anyhow, the "pitcher's luck" stat is called DER (defensive efficiency rate). More details on what it means and how the Nats are doing after the jump!

DER is basically BABIP from the pitcher's point of view: of all the times an opposing batter put a play into play, what fraction result in outs?  Again, part of this is the luck of where the hits land, part of it is the skill of the fielders, and part of it is the skill of the pitcher. The pitcher has no influence over the first two things, so DER gives us a way to see how lucky he is with seeing-eye singles and good/bad fielding behind him (Unlike BABIP, which only counts hits, DER counts errors, too).  If we take the league average BABIP as .300, that puts the league average DER at .700.  Anything much higher than that, and the pitcher has good luck/good fielding support; anything much lower, and the pitcher has bad luck/poor fielding behind him.

The other piece (to file under "pitcher skill") is ground-ball percentage (GB%). This is the percentage of balls put into play by opposing batters that are grounders.  Pitchers can influence this number by keeping balls low in the strike zone, where it's hard to hit them in air--especially sinkerball specialists like our own Shawn Hill. A high DER may be partly thanks to a high GB% as much as to luck or having a Zim at every base. We can also look at opposing LD% (line drives) for a sense of how often pitchers leave up a meatball that a hitter can really clobber.

I use ERA+ as a measure of how well people are pitching.  Like OPS+, 100 is league-average; more than 100 is above average; less than 100 is below average.

The Starters

Tim Redding (ERA+ of 134, highest of the starters) has a very high DER of .775, highest of the starters.  He's had some good games, sure, but opposing batting averages are likely to come up as the season goes on. His GB% is 46.3, lower than every starter not named Matt Chico. However, he is keeping batters off-balance, as his 16.0 LD% is lowest on the rotation.

John Lannan (125 ERA+) has been following his two-seam fastball to a team-leading 57.1 GB%.  A dead-average DER of 0.694 means he's getting his wins without having two highlight-reel catches out of Zimmy in the game (see Tim Redding, above).

Shawn Hill (104 ERA+) is using his heavy sinkerball to get a 54.2 GB%, good for second among the starters. His .689 DER means is maybe slightly unlucky, although his ongoing struggle to pitch through various pains are probably the reason he's not doing better.  We might expect slight improvement if his arm doesn't fall off.

Odalis Perez (98 ERA+) has an average DER of .695 and fair 48.9 GB%. Looks like league-average performance is what we're getting, and not an unreasonable thing to expect for the rest of the season. Given last year's rotation follies, league average is a standard I'm happy to meet!

Matt Chico (70 ERA+) has a 0.662 DER and only a 37.8 GB%.  He's giving up a lot of stuff hit in the air, and that means dingers and extra bases.  Another way to put it is that opposing batters' LD% is 23.6 (worst on the staff)--Matt turns every opposing batter into Nick Johnson!  Maybe Matt's a bit unlucky, too.

Jason Bergmann (57 ERA+) has a 0.672 DER and a 28.1 GB%. Can you say, 'fly ball pitcher'?  Opposing LD% is only 17.5, about average for the staff, so as long as those flies don't drift out, it might work.  We'll see how his numbers evolve over the season--maybe the next Columbus Mechanics (abbreviated windup) will help him turn the corner.

The Relievers

Saul Rivera (99 ERA+) has a 0.739 DER and 54.3 GB%.  He's getting good defensive support, but he's making opposing batters hit on the ground as well as Shawn Hill. That looks legit.

Luis Ayala (80 ERA+) has a slightly-below-average 0.690 DER but a lowish 40.2 GB%. His performance to date seems justified by the numbers. The mistakes are coming out of his throwing hand, not the gloves behind him (I'm shuddering remembering the Mother's Day loss, right now).

Jon Rauch (170 ERA+) has slightly-above-average 0.724 DER, a low 32.8 GB%, and a nervous-making 20.3 LD%. How is he doing it?  He manages more than 6 strikeouts for every walk, so the control is there, but he's striking out a bit less than one batter per inning.  I don't want to believe the Big Man's success is the result of voodoo powers, but it just might be. He gets a lot of fly balls, and his rate of infield pop-ups per fly ball is team-leading 20%, while his rate of Home Runs per fly ball is only 8.8% (second only to sinkerballer Shawn Hill).  Somehow he's getting 'em to strike out or fly out, while keeping 'em inside the yard.

Joel Hanrahan (103 ERA+) has a 0.721 DER, a 42.6 GB% and a 23.0 LD%!  Looks like "Wild" Joel has been a bit lucky, game-losing WPs notwithstanding.  Unless he brings more control to go with the heat, look for more fireworks in garbage time.

Jesus Colome (125 ERA+... really?) has 0.678 DER, a 28.6 GB% and a 37.5 LD% (worst on the team)! How the heck is he the "second best" reliever?  Against him, batters hit more line drives than Miguel Tejada!  He strikes out about a batter per inning, but he issues walks at more than half that rate, too.  His pacing around the mound must be a ritual for summoning voodoo powers--I'm glad Manny's not messing with that sort of dark mojo during close games.

What have we learned?

Lannan looks like a genuinely above-average pitcher. Redding might cool off a bit from where his now, but he seems to have it, too. Perez and Hill (if healthy) are legit league-average starters. The jury is out on Chico and Bergmann--they've had some bad luck, but plenty of bad pitches.  Going forward, we can expect a reasonable starting performance 3 or 4 times out of 5. The rotation looks like it's getting solid.

As for the relievers, Rivera and Ayala seem to match up to their good and bad reps this season (respectively), while everyone else seems to be living on borrowed time.  Are they all subconsciously emulating The Chief, making it exciting but somehow  mostly winning anyway?