ISO Risers and Droppers

Every season some players have a power breakout (Granderson) or meltdown (Dunn). I decided to look at the players with the highest and lowest ISO increases this season and the reasons behind the changes for a few of the players.

Below is a list of the biggest gainers and losers in ISO from 2010 to 2011 (min 400 PA each season):

Name 2010 ISO 2011 ISO Difference
Cabrera Asdrubal 0.071 0.189 0.118
Kinsler Ian 0.125 0.212 0.086
Granderson Curtis 0.221 0.304 0.083
Zobrist Ben 0.115 0.196 0.081
Molina Yadier 0.080 0.156 0.076
Upton Justin 0.170 0.244 0.075
Cabrera Melky 0.098 0.168 0.069
Braun Ryan 0.197 0.259 0.062
Gordon Alex 0.140 0.199 0.059
Victorino Shane 0.170 0.226 0.056
Wells Vernon 0.242 0.181 -0.061
Cabrera Miguel 0.294 0.232 -0.062
Martinez Victor 0.191 0.128 -0.062
Abreu Bobby 0.180 0.109 -0.071
Rios Alex 0.173 0.101 -0.072
Ethier Andre 0.201 0.129 -0.073
Werth Jayson 0.236 0.163 -0.073
Guerrero Vladimir 0.196 0.119 -0.077
Huff Aubrey 0.216 0.129 -0.087
Dunn Adam 0.276 0.124 -0.152

Asdrubal Cabrera so far has the highest jump and it is no surprise to to see that Adam Dunn is the leading decliner. The following is a look at the reasons behind the change for some of the hitters.


Jayson Werth: After signing a $126 million dollar deal with the Nationals this last off season, Werth has been a massive disappointment. After 3 straight 5 WAR or better seasons, he is likely to finish 2011 under 3 WAR.

It should have been expected to see the 32 year old’s home run total drop since the 2010 HR park factor for Philadelphia was 120 and it is 100 for Washington (a 20% drop). He averaged 29 HRs over the last 3 seasons in Philly. Taking into account park factors, he should have been near 23 home runs for 2011. His 18 so far isn’t that far off.

To further illustrate this point, here is a chart of his home run and fly ball batted ball distances over the last three years:

2009 to 2011: 294 ft
2009: 293 ft
2010: 290 ft
2011: 301 ft

He is actually hitting the ball with as much authority or more this season compared to the previous 2 seasons.

One change, that is a little harder to explain, is the drop in doubles. It is a more difficult to hit a double in Washington (2B PF =94) than in Philly (2B PF = 99), but he looks to hit 1/3 fewer doubles this season (28) than last season (46). The cause for this drop is hard to pinpoint. The normal causes – a drop in line drive rate and slower running – aren’t happening in 2011.

Werth’s drop in ISO from home runs was somewhat to be expected because of moving to a larger park. The problem for him this season has been a drop in doubles, which is significantly harder to explain.

Vladimir Guerrero: Vlad’s drop off can be attributed to simply not hitting the ball as hard this season. His batted ball data lines up with his career numbers except for his 7.8% HR/FB%. It is down from last season’s value of 14.6% (career average = 16.1%). This drop is easily seen in his batted ball distances for fly balls and home runs.

2010: 293 ft average
2011: 273 ft average

Hitting the ball 20 less feet is not going to help a player’s power numbers.

Risers (I have already looked at the reasons behind Granderson’s and Cabera’s increases this season.)

Ian Kinsler: Two-thousand and eleven for Kinsler is not any kind of breakout season. Instead, he is just putting the disaster of 2010 behind him.

Here are his career ISOs since 2007:

2007: 0.178
2008: 0.199
2009: 0.235
2010: 0.125
2011: 0.232

Even though 2011’s ISO is a career high, it is just 7 points higher than the one he posted in 2009. The reason for the 2010 drop was that Kinsler was hurt for much of the season. He started the season on the DL with a sprained right ankle. Then on July 29th, he hurt his left groin (BTW – Am I the only one that doesn’t need to know which side of the groin the injury is on? Once I hear groin, I pretty much know the general area). He missed a total of 53 games over the entire season.

Now that he is healthy, the 29 year old is back to putting of similar number that he did before 2010.

Park factors are courtesy of

Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

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Noting Jacoby Ellsbury’s ISO increase from 2009 (ignoring 2010) is a worthwhile addition.