Friday, August 6, 2010

Back-to-Back Against Travis Wood and Madison Bumgarner

Since the Cubs specialize in rookie pitchers, it's only fair that the Reds will send out Travis Wood on Sunday to face Thomas Diamond. It's also fair that Madison Bumgarner will take the mound Monday for the Giants in Carlos Zambrano's return to the starting rotation.

Wood and Bumgarner are left-handed rookies, both highly regarded. Using league adjusted stats, and setting average for each to 100 like OPS+ does, here's how their career lines, including time in the Show, stack-up.


BF K BH KBH GB LD FB PU
Wood 2048 113 107 115 89 102 106 139
Bumgarner 1722 118 66 190 95 110 99 118

Bumgarner has a slight edge in strike outs per batter faced (K) and a big advantage in walks and hit batters per batter faced (BH). As a result, Bumgarner's K:BH ratio is well above league average.

Batted balls, all per ball in play (including home runs), isn't as easy to read. Neither appears to be a ground ball pitcher, neither seems to be an extreme fly ball pitcher. Both do get a lot of pop-ups, particularly Wood.

While Bumgarner may have the edge with battles settled at home plate, Wood's batted ball profile may be more appealing. He's also had some impressive luck on balls in play, or weak contact, or outstanding defense.

Using linear weights (pitch-by-pitch, adjusted for the count) Wood as a rvERAa of 1.82 in the majors. That number comes from actual hits and outs on balls in play. If you change from actual hits and outs and use batted ball types (line drive, ground ball, fly ball, pop up) you get an rvERAe of 4.70 for Wood. rvERAa should be close to actual ERA (2.42), and rvERAe should be similar to xFIP (4.10). A big part of Wood's "luck" has been a lower than average rate of fly balls and line drives going for home runs. He's down at 4.2% while the league average is closer to 8%.

Bumgarner's rvERAa and rvERAe are 3.92 and 3.93, the former not mathching his ERA (2.97) and the latter almost right on his xFIP (3.92). Starting to feel like Bumgarner's pitching better early in their careers? Wood's ERA is a half run better, but regression is more likely to haunt the Red than it will the Giant from what we've seen so far.

Zooming in on the ability miss bats (Whiff) and throw strikes (B:CS and IWZ), along with another look at batted ball outcomes (SLGCON).

Whiff B:CS IWZ SLGCON
Wood .214 1.7 .535 .350
Bumgarner .191 2.0 .543 .517

Wood's unrealistically low SLGCON corresponds with the gap between his rvERAa and rvERAe. Both have good control and average whiff rates.

Wait, wasn't Bumgarner's control better than Wood's? Well, yes, but just by a little. That's because Wood's steadily improved as he progressed and carried it over to the majors. Here's how those league-adjusted stats look just for regular season play with their big league clubs.

BF K BH KBH GB LD FB PU
Wood 175 117 83 141 68 122 127 132
Bumgarner 251 108 75 149 111 90 99 65

While they've moved closer together with strike outs and walks, they've moved further apart batted balls. Small samples, so don't etch anything in stone.

Pitch Types

Both rookies are left-handed, but Bumgarner is 21 years old and is 6-foot-4 and 214 pounds. Wood is older, 23, and smaller, 5-foot-11 and 165 pounds. Bumgarner throws five pitches, Wood the same five plus one. Suprisingly, there's no real difference in their 2010 fastball speeds.

Both Bumgarner and Wood throw four- and two-seam fastballs. Wood's 91 mph fastball is thrown 41% of his pitches and Bumgarner's matching 91 mph is thrown more often, 53%. Wood throws a two-seam fastball on 23% of his pitches while Bumgarner uses it for just 6% of his offerings. Again, 91 mph for each, give or take a fraction.

Change-ups are a different story. Neither throws it often, Wood 10% and Bumgarner 7%, but they offer slightly different looks. Wood's change is just under 80 mph, on average, while Bumgarner's is up close to 83. Relative to their four-seam fastballs, Wood's moves 7 inches (tail and sink) and Bumgarner's 4. Wood gets more sink and arm side movement.

Their sliders are similar, both about average in terms of movement. Bumgarner throws his harder (85 vs. 82 mph) and far more often (23% vs. 3%). But Wood also throws a cutter on 17% of his pitches. It comes in at 88 mph, a nice spot in below fastball speed but clear above change-up and slider speed. Wood's cutter also has a few inches of glove side movement relative to his fastball along with some sink.

The fifth common pitch, and Wood's sixth, is none other than old Uncle Charlie. Actually, Bumgarner's (74 mph) can be a little slurvey while Wood's (73 mph) has nice 1-to-7 motion.

Before a look at all that stuff in PITCHf/x graph format, it's important to point out the differences in arm slot. Even if the speeds are similar, pitches with the same or similar grips will move differently due to the difference in arm slot.


Wood
Bumgarner
Photobucket


Not the greatest pictures, but Bumgarner is lower than Wood. You can see the same thing in their Spin Deflection charts. The arm angle can almost be superimposed over the spread of pitches.

Spin Deflection

Wood
Bumgarner


These charts (above and below) contain any pitch they've thrown in a PITCHf/x game, which means we have some 2009 regular season and 2010 Spring Training in Bumgarner's sample. He had some low velocity stretches, and you'll see his slider was down at some point, too.

These charts are spin axis (which gets messy with sliders, so don't read much/anything into that) and speed. It's just another way of looking at pitch groups, and it really shows the speed differences between pitches better. The spin deflection charts above are better for movement.

Spin Axis x Release Speed

Wood
Bumgarner

The Cubs frequently wilt against young lefties, so I will try and enjoy watching these guys pitch without sweating the outcome too much.


Wednesday, August 4, 2010

Out of the Arms of Babes

Thomas Diamond's impressive -- and bullpen sparing -- MLB debut marked the tenth appearance by a rookie pitcher for the 2010 Cubs. As of this writing, there are six rookies currently on the staff. That number will probably stay there while the revolving door shuffles guys between Des Moines and Chicago. Maybe the number of rookies will be seven or five for a day here or there. Maybe more. However you slice it, the Cubs have a very young group of guys, mostly in the bullpen.

By the time you meander your way through this, you'll know who these kids are, what they throw, how they've performed and, most importantly, who they've performed relative to an "average" National League pitcher and relative to their veteran teammates. In other words, we'll see how much all these kids have cost the Cubs in terms of wins and losses.

Before going too far, you may want to check-out this handy reference at Hardball Times. It contains definitions for almost all the stats and pitch types discussed below. Stats covered here but not there will be explained here. You may notice the last table in this article will be a lot like the first one at the reference link, but with more recent data.


update: some balls in play weren't included from recent games; fixed now and changes noted below

Cubs 2010 Rookie Pitchers - Playing Time

This will give you an idea of how small the individual samples are and how right-handed this group of rookies is. This numbers only include pitches captured by the PITCHf/x system and does not count pitch outs, intentional walks or anything that was simply not recorded.


PitcherThr.GBFPTP/BP/G
Thomas DiamondR1271204.4120.0
Mitch AtkinsR3321243.941.3
Justin BergR261154023.515.5
Jeff StevensR18823404.118.9
James RussellL361505623.715.6
Jeff GrayR7451573.522.4
Andrew CashnerR271304713.617.4
Casey ColemanR117633.763.0
Brian SchlitterR7451693.824.1
Esmailin CaridadR823974.212.1


G games, BF batter faced, PT pitches thrown, P/B pitchers per batter, P/G pitches per game

Cubs 2010 Rookie Pitchers - Pitch Types and Speed (mph)

Now the fun begins. This only covers 2010, so guys like Gray are not a complete picture. This is just a matrix of pitcher and type, with the average speed at release for each pitch, graphs follow with more details on speed and spin.


Pitcher4-seam fastball (F4)2-seam fastball (F2)Slider (SL)Change-up (CH)Curveball (CU)
Diamond8989768173
Atkins8990848376
Berg9091838478
Stevens92928573
Russell90908181
Gray929386
Cashner97978787
Coleman9090828177
Schlitter94938486
Caridad929278



Cubs 2010 Rookie Pitchers - PITCHf/x Charts

As usual, I've tossed the Gameday classifications and use my own. These charts, in case you're wondering, are generated in R using templates based on Dave Allen's work, if I'm not mistaken.

Some of the groupings may look odd, as the data is not corrected for camera alignment issues etc. Classifications are generally done on a game-by-game basis, which usually takes care of that in terms of accuracy of my labels. For each pitcher, you'll get two charts. Speed and spin axis is first, it shows the velocity of a pitch and the angle of the axis of the ball's spin. That may be meaningless, so the charts are labeled by direction of break. The second chart throws speed out and breaks spin into two components. The horizontal and vertical spin deflections are shown in inches, from the catcher's perspective.

If these look like Rorschach tests to you, just scroll down past them for more numbers and a little commentary.

Justin Berg




Mitch Atkins




Thomas Diamond




James Russell




Jeff Stevens




Casey Coleman




Andrew Cashner




Jeff Gray




Esmailin Caridad




Brian Schlitter




Cubs 2010 Rookie Pitchers - Batted Ball Distributions

Remember, we're dealing with some silly small sample sizes that get smaller when it's just balls in play (including home runs).


PitcherGB%LD%FB%PU%HR/FL%
Diamond29%29%29%14.3%0.0%
Atkins38%19%29%14.3%10.0%
Berg47%18%30%4.5%4.7%
Stevens41%16%38%5.2%12.9%
Russell28%17%44%11.4%13.0%
Gray65%6%29%0.0%8.3%
Cashner52%22%21%4.4%15.4%
Coleman54%38%8%0.0%0.0%
Schlitter36%24%30%9.1%11.5%
Caridad46%8%38%7.7%16.7%

updated 910pm

Cubs 2010 Rookie Pitchers - PITCHf/x Metrics

The rvERA shown in the Hardball Times article on benchmarks is a combination of two other metrics, rvERAa and rvERAe. "a" uses actual outcomes on batted balls, hits and outs as they actually happened. "e" ignores actual outcomes and uses the linear weights associated with batted ball types, liners, pops, flies and grounders.


PitcherrvERAarvERAeSwingWhiffB:CSIWZChaseWatchnkSLG
Diamond3.903.07.483.3102.3.483.355.346.571
Atkins5.735.50.403.2402.1.532.207.396.571
Berg4.596.50.445.1233.0.530.223.312.348
Stevens6.654.87.382.1772.6.453.168.331.690
Russell5.354.50.496.2331.9.543.273.286.588
Gray9.084.97.420.1673.0.490.200.344.588
Cashner5.905.21.427.2542.5.512.236.337.600
Coleman10.778.35.444.1073.3.524.133.227.615
Schlitter10.256.00.456.1692.8.515.195.291.834
Caridad7.764.81.361.1712.8.443.167.324.538

rvERAe, nkSLG updated 910pm

Cubs 2010 Rookie Pitchers vs. Others

Here's where we get into some larger sample sizes, especially when we look at the entire National League. This is a big roll-up of all the pitchers above, plus the rest of the Cubs staff and the aforementioned senior circuit.


GroupGBFPTrvERAarvERAeSwingWhiffB:CSIWZChaseWatchnkSLGGB%LD%FB%PU%HR/FL%
Rookie Cubs7166625056.275.23.440.2032.5.510.226.317.57443%18%32%6.9%10.7%
Other Cubs1073433130844.264.02.449.2372.0.514.276.350.51543%19%30%8.2%7.2%
All Cubs1074099155894.584.22.447.2322.1.514.268.344.52543%19%30%7.9%7.8%
NL835636512477914.284.30.444.2182.0.512.270.354.51045%20%28%7.3%7.3%

rvERAe, nkSLG, GB, LD, FB, PU, HR/FL updated 910pm

In a nutshell, the kids take an above average staff (warts and all) and make it below average. How much? It sorta depends on how you look at it. Let's do some quick back-of-the-envelope math.

First, the Cubs defense has been sub-par in 2010. Baseball Prospectus has them fourteenth in the NL in defensive efficiency. This screams "use fielding independent metrics". In my case, that's "e" linear weights which are based on batted ball types and ignores actual outcomes. Even home runs per ball in air are regressed to league average with the "e" metrics.

The Cubs staff is 9 runs better than average in 2010. The non-rookie pitchers have been 25 runs better than average, and the rookies 16 runs worse than average. Those aren't even clean numbers, as relievers and starters are being treated equally. With the exception of Diamond, the rookie innings have been in relief. More so, "average" is not the same as "replacement" so they way we usually convert runs to wins is not what I'm doing here.

runs against average have been corrected 910pm

Without doing the calculations of leverage and all that good stuff, I'll say the Cubs rookies have been two wins below average in 2010 (roughly 10 runs per win, depending on run environment). A check of Fangraphs shows the rookies around 1.8 wins below replacement (which is not the same thing as average, and the park adjusted FIP they use is not equivalent to my "e" metrics).

OK, so that was a lot of work to do what took 15 seconds at Fangraphs, but I enjoyed the ride. I do end up understating the quality of the Cubs veteran pitchers, though.

But this is about the rookies. They've been about a two win cost so far. With more and more rookie innings to pile-up, things could get worse, or, if the kids adapt, better. Even if this youth movement, forced or otherwise, costs the Cubs three wins by the time October rolls around, it will probably be worth it. It's not like they'll finish three games out of first place. Maybe out of fourth place.


Monday, August 2, 2010

The Cubs Pitchers are a Bunch of Babies

The current Cubs pitching staff and their ages as of 8/2/2010.


Justin Berg 26
Andrew Cashner 23
Casey Coleman 23
Ryan Dempster 33
Thomas Diamond 27
Tom Gorzelanny 28
Carlos Marmol 27
Sean Marshall 27
James Russell 24
Brian Schlitter 24
Mitch Atkins 24
Randy Wells 27
Carlos Zambrano 29

Dempster, who is 33 going on 14, is the staff elder. Big Z is the senior statesman in the bullpen. Let those two facts sink in.

To top off the youth movement, the everyday line-up has a middle infield with a combined age of 44 and a 24 year old somewhere in the outfield.