Are the D Backs likely to regress ?

Within a few hours of Buster Posey's injury, an article appeared on Fangraphs:

Buster Posey's Injury opens door for Colorado

The heartless bast...........oh wait....thats not what this post is about.

In the text of the article was this:

The Giants currently hold a 2.5*  game lead on Arizona,  a team which will likely regress, and a three game lead on their real competitor, Colorado.


*lead reduced to 1.5 since that writing

And that was the extent of any mention Arizona got in the article. Completely dismissed as an afterthought, A team that is playing over it's head. Due for regression.  See Ya.  Rather galling, eh ?.  Why would they say that ? Lets find out.  

So how do we usually look at these things. The first thing I do is a quick check of the team's RS & RA, and the Pythagorean Won-Loss.  (You can always see this at the top of the  Baseball-Reference Team Page . It's usually a good "quick and dirty" snapshot of how things might be going for the team beyond W-L record.  We all remember how the 2007  team won 90 games despite getting outscored by their opponents 732-712 on the season. According to their "pythag", they should have been a 79 win team.  That was analyzed to death. In the end it was pretty much concluded that this occurred primarily due to two factors:  Lights out high leverage pitching from the bullpen who almost all had lower ERA than their peripherals would have suggested, and a lot of really well timed productive pinch hit at bats in high leverage situations. Alas, neither turned out to be much in the way of repeatable skill for that group of players.

So what of the team's pythag so far ?  Coming into tonights game  they had scored and allowed the same number of runs,  221, which of course gives them a 25-25 Pythag, just one game worse than their actual won loss. So whats the big deal ?  Why would the Fangraphs writer dismiss the D Backs as a team due to regress ?

Here is your first clue:

D Backs 1697 221 416 95 8 53 686 165 383 .245 .316 .404 .720
Opponents 1694 221 431 96 8 54 705 160 344 .254 .321 .416 .738


Despite being out "OPS'd" by .018 and having a total base deficit of 19, (due to 15 less hits, including 1 less homer and one less double), AZ has scored the same amount of runs as their opponents.  We know it's not because  they put the ball in play more than the other team, making good things happen. They've K'd 39 more times than the other team.

So are the D Backs getting lucky ? Why are they scoring the same amount of runs when it appears they should be getting outscored by at least 5-10 runs ?

Here are some possible reasons:

BA risp OPS hi lvg GBDP SB CS
D Backs .248 .775 21 44 17
Opponents .234 .691 40 19 9

Lets Break these down one by one:


AZ  hitters are 107 for 432 W/ RISP and have a .294 BABIP. This is right in line with their season numbers, and I don't see any reason this should change.

AZ Pitchers on the other hand have batting against of 92 for 394,W RISP and have just a .258 BABIP against.  I'll get to why they have had fewer at bats against w/RISP despite allowing a similar total number of baserunners. However I think we can pretty much count on the .258 BABIP in these situations comiung up a fair amount.  I'd be VERY surprised if that number was lower than .280-.285 by the end of the season, which means it's probably going to be .300 from heere on out. 

So expect BA w/RISP against to RISE.

OPS in High Lvg situations:

This one really scares me.  Obviously an improved bullpen has somethng to do with this.  If our relievers are pitching in late high leverage situations and doing better than the other team's relievers, that explains some of this. But that gap is huge. There simply is no reason the D Backs shoud be 84 points better than the other team in this category.  This gap is going to close. And it's going to be frustrating to watch.   The good news here is that the team Bullpen ERA is pretty close to their FIP and xFIP.   3.32 ERA, 3.50 FIP, 3.52 xFIP.  So not really flukey as a group.  If they stay healthy, we should not expect the bullpen to regress too much.


Ok...wait a minute. We all know we have a fly ball staff. So how the heck has that staff induced twice as many GBDP's as the other team ?

On offense our team has hit into 21 DP in 327 DP situations, or 6% of the time.  Thats tied with Seattle for the lowest (best) DP ratio in the league.  The low rate, combined with the low number of opportunities in the first place, 5th fewest) has lead to the fewest DP into in the majors.  This is somewhat repeatable. The team hits the fewest Groundballs of any team in the NL and 5th lowest total of any team in the majors.  They also have the 5th highest K% in the majors. (yes, they've improved, but they still strike out a lot). So with few GB ad alot of K's, and a team that we know runs well on the whole, it's not shocking they could avoid DP's.

On the pitching side however, it's another story.  The team has the 4th lowest GB percentage in the majors, yet is tied for 7th in GBDP's induced.  That just does not add up.  Inducing twice as many DP's as you hit into is not sustainable with these underlying peripheral numbers. 


Ok, here is an area where doing the little things right is paying off, and it IS sustainable, in my opinion.  We all have read how they have worked on holding runners on, and it's really paying off.  Amit mentioned this in a tweet and in the D Backs Factoid Dump thread over at the bullpen.  However based on work that has been done showing the Value of base stealing which can be read over at Beyond the Box Score, this amounts to less than 5 runs total value, even if you round up and account for leverage.


The above are just a few data points to show how underlying factors can affect a team's runs scored and runs allowed beyond the standard BA/OBP/SLG .  In the case of most of these, it's not really repeatable skill, (BA W/RISP, HI LVG OPS, or the GBDP gap), or in the case of the SB differential, not really all that significant.

There are other reasons the writer in that article said the team is due to regress.  They reference Baseball Prospectus Adjusted Standings and also Playoff Odds Report .  The  "2nd and 3rd order" wins portion of that adjusted standings report is based on  much more in depth and sophisticated ways to look at these underlying  factors than I am talking about above. In the playoff odds report they  also factor in projections and whether a team is over or underperforming their projections by a great deal. As a group, the D Backs probably are overperforming their projections.

Of course none of this should cause us to dismiss this team's chances like the Fangraphs writer did. Gibson has this team fighting for every single inch of turf they can get.  Both Colorado and SFO have their own issues. As I type the D Backs just erased a 6 run deficit in Houston and lead 7-6 in the 9th.  Win or lose, they fight. They come back. They don''t give up.  It's tough to maintain over 162 games.  But what we are seeing definitely is better than what we have had and there is plenty of reason to be excited.  For me , I tend to be a fan by night, and an analyst by day. These two sides of me are often in conflict.  But I still enjoy the games even when the analyst side of me shows reason to be cautious with my optimism. So should you, even after reading this article.  Just don't get carried away.

Update: Jim, not sure if you can at this point, but if possible, please help edit the regression post and add the attached updated table AFTER the last paragraph. In the last 4 games the team has outscored opponents 37-15, and blown by them in every accumulative stat. Yet another lesson in the perils of small sample size. And yes, team stats through 50, (or 54 games) is a small sample size.

AZ 50 1697 221 416 95 8 53 686 165 383 .245 .316 .404 .720
Opp 50 1694 221 431 96 8 54 705 160 344 .254 .321 .416 .738

AZ 54 1845 258 465 102 10 62 773 181 414 .252 .322 .419 .741
OP 54 1830 236 462 100 8 56 746 172 372 .252 .319 .408 .727
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