Koji 2014: Great or Historically Great (Again)?

ScubaSteveAvery

Master of the Senate
SoSH Member
Jul 29, 2007
8,329
Everywhere
In case you need reminding of what Koji did last year: from June until September Koji appeared in 53 games, pitching 53.1 innings, allowing only 17 hits, 5 runs (only 4 earned - 0.68 ERA), and 5 walks, while striking out 72 batters.  During that time period, batters posted a .097/.126/.154 line.  His BABIP was a ridiculous 0.155. He allowed only 1 HR during those 53 innings. He continued that dominance into the playoffs and we all know what happened in October. 
 
Expecting Koji to post those numbers again is both unfair and unrealistic.  For one, those 53.1 innings were possibly the greatest stretch by a reliever in baseball history. And for two, Koji is 39 years old and coming off of the most innings pitched in his MLB career by far.  He used to be a starter in Japan, but hasn't' started since 2009 when he first joined Baltimore. Even then he only pitched 66 innings over 12 starts.  However, measuring this year compared to most of last year can be instructive.  For one, its what Koji aspires to replicate this year.  Plus, we can tell what he isn't as successful doing this year compared to last, since the distinction will be brighter.  And who knows, maybe he'll come close to it and we can all be happy.  Even a slightly worse Koji will still be a very valuable asset. 
 
On the surface in 2014 we have seen the tale of 2 Koji's.  For the first 5 games of the year he was just as automatic as before, pitching 5 innings, allowing 3 hits, no runs, no walks, and striking out 7.  Hitters were only hitting .158/.158/.211 with a .250 BABIP.  Then he was shut down for a week with shoulder tightness.  Since returning from his week off, Koji has been a different pitcher: 10 games (9.2 IP), with 10 hits allowed, 2 earned runs (1.86 ERA), 3 walks, and 15 strikeouts. What has changed is that batters are hitting .278/.333/.444, with a BABIP of .421, off of him in that 10 game stretch.  The BABIP number really stands out to me as it is way above his career norm:
 
Koji Career MLB BABIP (As a Reliever)
Year BABIP
2010 0.296
2011 0.197
2012 0.203
2013 0.189
2014 0.355
 
 
Outside of 2010, his BABIP has hovered around .200.  This is interesting for a couple of reasons.  The first is that pitchers generally have little control over their BABIP.  They rely on defense to make plays, and a bad defense can increase the BABIP.  The second is that BABIP is usually not as consistent from year to year, given the just mentioned defensive fluctuations.  Koji has kept a consistent BABIP over 4 seasons, playing for 3 different teams.  Even if we expect some regression, its fair to say part of Koji's struggles since coming back have been bad luck related. Koji said last week (link) that this is an April/May thing and that last year he didn't pitch that well during the same period.  I took a quick look at his stats from last April/May and found that he was partly correct.  He still pitched very well for relief pitching standards, but nowhere near what he did from June to September: 22 games (21 IP) allowing 16 hits, 5 earned runs (2.14 ERA), 4 walks, and 29 strikeouts.  Batters hit .205/.244/.423 with a .267 BABIP.  It is certainly possible that he is a better warm weather pitcher than cool weather pitcher.  We know that his second half stats are vastly better than his first half stats for his career. His K/BB ratio is six times better in the second half than first half, and his ERA drops by a run. 
 
However, its still important to look at that .421 BABIP and see whether this is just typical early struggles, or a result of age/injury-related decline in stuff.  I took a look at his batted ball profiles for 4 different periods:  April/May of 2013, June-Sept of 2013, 2014 pre-shoulder injury, and 2014 post shoulder injury.  As always, the 2014 stuff is subject to SSS bias, but if any trend sticks out we should be able to see it.  The batted ball data is from Baseball-Reference, which was the only place to aggregate intra-month data. Fangraphs has his GB% as lower, and LD% about 10% lower.  I cross-checked with pitch F/X data from BrooksBaseball and both his fastball and splitter LD/BIP percentages were in the mid 20s, so I kept the B-Ref data. 
 
[tablegrid= Koji Batted Ball Statistics ]Stat April/May 2013 June-Sept 2013 2014 Pre-Injury 2014 Post-Injury Strike% 70% 76% 75% 68% Strike Looking % 19% 17% 19% 13% Strike Swing % 15% 20% 19% 19% GB% 32% 46% 33% 36% FB%   68% 54% 66% 64% LD% 12% 14% 25% 23% PU% 14% 17% 33% 9% K% 35% 40% 37% 38% BB% 5% 3% 0% 8% BABIP 0.267 0.155 0.250 0.421 Pitches/Batter Faced 4.03 3.92 3.58 3.90 [/tablegrid]
 
A couple of things stand out.  The first is that the main difference between April/May 2013 and June-Sept 2013 was the reduction in fly balls and the increase in ground balls.  His line drive and pop-up rate stayed consistent between the two period, but he traded fly outs for ground outs.  Since ground balls are more likely to go for hits than fly balls (ex line drives), we can assume he had weak contact on the ground balls, and a solid infield defense behind him, or both. 
 
What is driving that high BABIP this season is likely the large increase in line drive percentage, since line drives fall for hits about 70% of the time.  Since coming back from his week off for the sore shoulder, his strike percentage has decreased, especially the strike looking percentage.  Before his injury he was getting lucky that the spike in LD% wasn't resulting in more hits. His walks have increased as well, which is expected when strike percentage decreases, but he still isn't walking the park.  
 
This probably raises the question of why the LD% has spiked all season (before and after injury). Koji's main issue this year, compared to June-Sept of last year is his performance against RHH.  Righties have feasted on both his fastball and splitter this year:
 
[tablegrid= Koji Batted Ball vs RHH ] 2013 June - Sept 2014   2013 June-Sept 2014 Pitch Outcome Fastball vs RHH     Splitter vs. RHH   Strike 35.5% 31.0%   41.0% 31.3% Ball 22.8% 29.6%   20.8% 21.9% Whiffs 12.7% 12.7%   29.5% 25.0% BIP 14.8% 15.5%   16.2% 21.9% GB/BIP 32.1% 18.8%   57.1% 71.4% LD/BIP 17.9% 27.3%   10.7% 14.3% FB/BIP 25.0% 36.4%   17.7% 14.3% PU/BIP 25.0% 18.2%   14.3% 0.0% AVG 0.143 0.429   0.074 0.308 SLG 0.262 0.714   0.130 0.539 BABIP 0.214 0.455   0.103 0.500 [/tablegrid]
Although he hasn't succeeded with both pitches, his fastball seems to stand out as the worse pitch against RHH. It is an easier pitch to command than the split, and we can see that hasn't thrown it for as many strikes this year. The whiff rate is the same, and the amount of times it is put in play has slightly up ticked, but the issue is what happens when it is put in play.  Compared to most of last year, the ground ball rate has plummeted and the line drives have spiked, leading to right-handed batters slugging .714 against his fastball.  The usage of the splitter has completely changed this year.  As you'll see in the charts below, he has switched the side of the plate he is working RHH with the splitter. 
 
I used Brooks Baseball to look at his fastball zone charts against RHH for this year, and June-Sept of last year. 
 

 

 
As would be expected, the issue is one of location.  He loves to feed RHH fastballs on the outside part of the plate.  However, this year he has missed outside 7% more than last June-Sept, especially in the middle-outside spot.  He is pitching up and away more than last year too.  But the main takeaway is that he has not located his fastball in the bottom part of the zone at all. Last year, we saw 13.24% of his fastballs hit the bottom third of the zone, most of them middle-away.  This year, just 1 fastball has hit the lower outside portion of the zone.  When you throw 89mph fastballs up in the zone, you are going to hit hard. 
 
The same goes for the splitter.  His troubles in keeping it down this year are really surprising.  Again, when splitters elevate, they flatten and are easier to hit.  Here are this splitter zone charts against RHH from last year June-Sept and all of this year:
 

 

 
Last year he fed RHH a steady diet of splitters down and away, sparingly coming inside.  This year, he has only throw 4 splitters down and away to RHH and has come inside a ton. Over half his splitters thrown have been inside.  Even more troubling is the most are inside and up in the zone.  Its unclear whether he is just missing inside, or if this is an approach change by Koji and staff.  What we do know is that it is not working. 
 
I don't think its time to worry about Koji at all.  He is still pitching well, but the biggest reason he isn't replicating last year dominance is that he isn't locating his pitches as well. If he can start placing it in the lower part of the zone, and using his splitter outside more, then I expect the ground balls to increase and the line drives to decrease.  
 

StupendousMan

Member
SoSH Member
Jul 20, 2005
1,909
I watched today's game (May 11 vs. Texas) and noticed that most of Koji's pitches were regular fastballs: only 3 of 11 were split-finger fastballs, all the rest were 4-seamers.  Hmmmm.   "Isn't the split-finger his best pitch?" I wondered.  So, I checked the BrooksBaseball player card for Koji.  Take a peek at the distribution of his pitches:
 

 
During the second half of 2013, when he was at his best, roughly half of the pitches were the split-finger variety.  That was the highest fraction of splitters in his American career; was it just a coincidence that it was also his period of otherworldly dominance?
 
As you can see, this year, he's only throwing the splitter about 1/3 of the time.  As I watched today, it seemed to me that he was
trying very hard to stay at the hairy edges of the strike zone with the regular fastball.  Since it only goes 87-89 mph, and doesn't appear to have a lot of movement, I can see why he doesn't challenge the hitters very often.
 
Was there something special about last year that allowed him to throw the splitter so frequently?   Did he find some special way of holding the ball?   Why might he be throwing fewer of the splitters now?  Do they put extra stress on his arm in some way?
 
I guess it will be interesting to watch what happens over the next few months: will he continue to throw the splitter sparingly, and will the hitters have better success against him?   Of course, "better success" might still mean an OPS of just 0.600 or so, which would still mean that he would be a valuable reliever.
 

Red(s)HawksFan

Member
SoSH Member
Jan 23, 2009
20,676
Maine
StupendousMan said:
Was there something special about last year that allowed him to throw the splitter so frequently?   Did he find some special way of holding the ball?   Why might he be throwing fewer of the splitters now?  Do they put extra stress on his arm in some way?
I recall Schilling once spoke about how touch and feel with the split can come and go because of the way the tendons in the fingers get stretched as they're split around the ball.  Sometimes they get too loose and the grip is affected, so the pitcher has to make adjustments and tweaks to get it back.  Could be that last summer/fall, Koji had the grip, pressure, release, etc all dead on perfect, and now he's lost the feel a bit.  It's probably a credit to him if he's recognizing that and not relying on it so heavily while it isn't as sharp.
 

SouthernBoSox

Member
SoSH Member
Jul 23, 2005
12,084
He said in an interview he isn't happy with his splitter right now because he was keeping it up.

With that said, he got 2 swings and misses on 4 splitter today.
 

EricFeczko

Member
SoSH Member
Apr 26, 2014
4,823
Red(s)HawksFan said:
I recall Schilling once spoke about how touch and feel with the split can come and go because of the way the tendons in the fingers get stretched as they're split around the ball.  Sometimes they get too loose and the grip is affected, so the pitcher has to make adjustments and tweaks to get it back.  Could be that last summer/fall, Koji had the grip, pressure, release, etc all dead on perfect, and now he's lost the feel a bit.  It's probably a credit to him if he's recognizing that and not relying on it so heavily while it isn't as sharp.
I wouldn't be surprised if the cold weather to start the season may have thrown off Koji's feel. The grip for a split-finger fastball requires one to hold the ball with the side of one's fingers, and the sides of one's fingers have reduced sensation relative to the tips. Cold weather would reduce the sensation further. The reduced somatosensory information would limit feedback that is important for adjusting the grip, pressure, and release points.

If that's the case, Koji might start getting better with the split towards the summer, and we will see increased usage then.

 
 

teddywingman

Looks like Zach Galifianakis
SoSH Member
Jul 31, 2009
11,168
a basement on the hill
SouthernBoSox said:
He said in an interview he isn't happy with his splitter right now because he was keeping it up.

With that said, he got 2 swings and misses on 4 splitter today.
He definitely left a couple that crossed the plate between the knee and the belt, but they both had very nice late dropping action. I know he wants that pitch to be near the dirt when it's caught, but today's splitters looked good to me.
 

ScubaSteveAvery

Master of the Senate
SoSH Member
Jul 29, 2007
8,329
Everywhere
StupendousMan said:
I watched today's game (May 11 vs. Texas) and noticed that most of Koji's pitches were regular fastballs: only 3 of 11 were split-finger fastballs, all the rest were 4-seamers.  Hmmmm.   "Isn't the split-finger his best pitch?" I wondered.  So, I checked the BrooksBaseball player card for Koji.  Take a peek at the distribution of his pitches:
 

 
During the second half of 2013, when he was at his best, roughly half of the pitches were the split-finger variety.  That was the highest fraction of splitters in his American career; was it just a coincidence that it was also his period of otherworldly dominance?
 
As you can see, this year, he's only throwing the splitter about 1/3 of the time.  As I watched today, it seemed to me that he was
trying very hard to stay at the hairy edges of the strike zone with the regular fastball.  Since it only goes 87-89 mph, and doesn't appear to have a lot of movement, I can see why he doesn't challenge the hitters very often.
 
Was there something special about last year that allowed him to throw the splitter so frequently?   Did he find some special way of holding the ball?   Why might he be throwing fewer of the splitters now?  Do they put extra stress on his arm in some way?
 
I guess it will be interesting to watch what happens over the next few months: will he continue to throw the splitter sparingly, and will the hitters have better success against him?   Of course, "better success" might still mean an OPS of just 0.600 or so, which would still mean that he would be a valuable reliever.
 
Interesting observation about the frequency of the splitter.  Today he still had the same issue with pitches missing the bottom third of the zone.  Outside of the splitter to end the game, everything was up, especially to RHH:
 

 
Looking at the 2013 heat maps again, I wonder if the issue is that his fastball sets up his splitter.  Since he is missing spots with the fastball, he cannot throw the splitter with the same deception.  If you look at the distribution of fastballs from 2013, you see that he throws them either belt high outside, or keeps them low and outside.  This sets up a split that he either starts at the belt, making it look like a fastball, and having it drop for a strike on the outside.  Or he starts it low and has it dive into the dirt.  But since he is also locating fastballs in that same low and outside spot, it keeps hitters honest about whether they are seeing a fastball or a splitter.  Without the fastball hitting those locations, he loses some deception.  Now, hitters can just sit on a mid to high 89mph fastball. 
 
I'm curious to know whether he is really just missing his spots that badly, or if the pitching staff has decided to mix up his approach (more fastballs, and splitters in).