BtB Power Rankings: Week 8

"On Paper" Playoff Leaders (based on rankings above)

American League: E=Yankees, C=Twins, W=Rangers, WC=Rays
National League: E=Phillies, C=Cardinals, W=Padres, WC=Diamondbacks*

This Week's Feature: The Arizona Diamondbacks

The Diamondbacks had a nice week, winning 4 of 6 and scoring 8+ runs on four consecutive nights, starting with a 13-1 crushing last Wednesday.  This vaulted them into the on-paper wild card slot, taking over the slot previously held by the victim of their 13-1 victory, the Giants.  It also propelled them just ahead of the Cincinnati Reds, who also had a good week and now are suddenly ranked 12th overall in the power rankings.  

This may seems surprising, because going into play tonight, the Diamondbacks are 20-26 (.435 W%), last in the NL West.  And their Pythagenpat winning % is almost exactly the same (.432 pW%).  And yet our component winning percentage, which feeds into the Team Performance Index that determines the ranking, estimates their expected winning percentage at .559!  Obviously an enormous difference.

What's going on?  The component-based estimated runs scored is pretty similar to reality, 228 actual vs. 220 expected (after park adjustments).  If anything, maybe the offense has overachieved, if only slightly.  What is driving the difference is a massive, huge, enormous difference in expected runs allowed: 262 actual vs. just 195 estimated!  

The Diamondbacks pitchers collectively have an awful 5.71 ERA.  This is despite playing in front of what our fielding statistics tell us is the third-best set of gloves in the National League (+16 runs).  Their FIP is better at 5.16--but still not good.  But their tERA (via statcorner.com) is 4.66.  And their xFIP is just 4.45.  That's not world-beating, but it's respectable--and a 1.26 run per 9 game  better than their ERA.  The biggest factor in all of this appears to be their team home runs per fly ball, which is currently a ridiculous 14.9%.  There is such thing as HR/F skill, but it's typically masked by volatility...and at the team level, and just can't imagine that this is indicating anything other than a lot of bad luck with the long ball.

Staff ace Dan Haren more or less typifies the Diamondback staff.  He has a 4.79 ERA, but a 4.06 FIP and a miniscule 3.18 xFIP right now.  Haren's problems have been high BABIP (0.346) and a 16.9% HR/FB ratio, but probably not anything to do with how he's actually throwing the ball.

None of this is to say that the Diamondbacks are going to play like a 0.556 team over the rest of the season.  But my guess is that they are likely to play better than they have.

Converting Runs to Wins

G=Games
RS = Actual Runs Scored, after a park adjustment
eRS = Estimated Runs Scored, after park adjustment (see "Offense" table below)
RA = Actual Runs Allowed, after a park adjustment
eRA = Estimated Runs Allowed, after park adjustments (see "Defense" table below)
W% = Actual Winning Percentage
pW% = PythagenPat Winning Percentage, based on actual runs scored and run allowed totals
cW% = Component Winning Percentage, using estimated runs scored and estimated runs allowed totals.  If you don't like the league adjustment, click in the header and sort by this column.
LgAdj = League adjustment, based on differences in league quality (justification here and here).
TPI = Team Performance Index, a hypothetical winning % based on component estimates of runs scored and runs allowed after the league adjustment.

Team Offenses and Defenses

RS = Actual Runs Scored
eRS = Estimated Runs Scored: wRC + EqBRR
wOBA = The Book's statistic, but park adjusted, and using data from both wRC and EqBRR
OBP = On Base Percentage (Times on Base / Plate Appearances)
SLG = Slugging Percentage (Total Bases / At Bats)
wRC = From FanGraphs, with baserunning removed, after park adjustments
EqBRR = Dan Fox's composite baserunning statistics from Baseball Prospectus, minus stolen bases since they are included in wRC.
Clutch = "Clutchiness" measure from fangraphs; difference between actual WPA and expected WPA based on component statistics.  We report this in runs.

RA = Actual Runs Allowed, after park adjustment
eRA = Estimated Runs Allowed: tRuns - Field - Catch
ERA = Straight-up Earned Run Average
FIP = Fielding-Independent Runs, based strictly on K-, BB-, and HR-rates.
xFIP = Experimental Fielding-Independent Runs from FanGraphs.  Like FIP, but with HR/Outfield Fly Ball rates regressed completely to league average.  xFIP is as predictive as any other DIPS-like stat.
xFIPrns = Pitching Runs Allowed, based on xFIP
Field = The average of team UZR and team DRS (minus rSB since I calculate catcher fielding separately).
Catch = Catcher Fielding Runs, based on SB's, CS's, WP's, PB's, E's, and this year catcher interference.  The methods are essentially those described here.  But I'm using B-Ref data this year, and so there are slight tweaks to the methodology, generally in ways that should lead to greater precision.
BABIP = Batting Average on Balls In Play.  Fluctuates at the team level with fielding, although chance events can have effects as well.