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Will They Rebound? A Look at the Largest ISO Decliners

Posted By Mike Podhorzer On June 6, 2011 @ 8:15 am In Meta Analysis | 15 Comments

As we are well aware, offense and power are down around the league once again. Home runs per game are at their lowest mark since 1992 and ISO is tied with 1993 for lowest since. Below are the five hitters who the biggest declines in their ISO rates versus last season. Using my mastery of sabermetrical statistics and my expert scouting eye, I will attempt to determine which, if any, of these hitters will rebound, making that particular player a good trade target.

Coming off a concussion and now dealing with a pinched nerve in his neck, it should be no surprise to see Justin Morneau atop this list. The pinched nerve has limited him in the weight room, which would clearly have an effect on his power, and he expects the issue to linger all season. His HR/FB ratio is just 5.0% after typically sitting in the mid to high teen range. It is hard to believe that his power would be so hampered that his HR/FB ratio will remain this low all year, but his health problems are quite serious. I do not think he will rebound from this slow start, at least not enough to resemble anything close to the Morneau we are used to seeing.

There have already been three articles written about Adam Dunn over the last month, so we know how much he has struggled. He has been dropped to seventh in the order, even against righties. Unfortunately, I do not have anything more to add to what has already been discussed in the aforementioned articles. He does fit that “old player skills” prototype, so it would seem to be in the realm of possibility that this truly is the year that Dunn is done. Just from memory, it seems like these types of players see their production drop off a cliff very suddenly, as opposed to a more consistent decline other types of players experience. But I can be wrong. He is only 31, so although he may look lost at the plate (and I hate that expression) right now, I would still bet that a surge will come sooner or later.

Dustin Pedroia‘s HR/FB ratio has dropped to 6.1%, from 11.4% last year, which is one of the primary culprits of his ISO decline. However, if we look at his HR/FB ratio history, it appears that 2010 could very well have been the outlier. In no other year has he posted a HR/FB ratio above 7.8%. His doubles rate is down dramatically as well, so it is actually all types of power that is missing. Oh, and he is striking out at easily the highest rate of his career. Interestingly, his walk rate is also a career best. It would seem that for some reason his plate approach changes. Maybe the broken bone in his foot that he suffered in late June of last year and essentially caused him to miss the rest of the season (he played in two games in August) is playing a role here. Given the change in his other metrics and a history of HR/FB ratios supporting his mark this year, I say his power does not rebound.

Two home runs in 190 at-bats. I am talking about Jason Bartlett right? Nope, Aramis Ramirez. After his strong second half last year, it is quite a surprise to see his power MIA so far this season. His doubles rate is up though, which is a good sign, but it could also mean that his power has declined into the warning track variety. Nearly all of his underlying metrics are right in line with his career marks, which makes his lack of power all the more puzzling. The only thing I could find is that he is swinging at a career high 35.2% of pitches outside the strike zone versus a 29.2% league average. Logic tells us that it is harder to hit a home run on a pitch outside of the zone than inside it, so this is definitely part of the problem. The question then becomes whether this O-Swing% continues or the old, powerful Aramis shows his face again. Since this is really the only red flag I could find and he is only 32, I would bet on a rebound. Of course, I am a little biased since I recently traded for him and in dire need of his power stroke.

Since Nick Swisher is unlikely to contribute in batting average (last season’s .288 mark was a BABIP-fueled luck fest that will not happen again), he becomes worthless in mixed leagues if he is not providing any power. Like Aramis, all the underlying skill metrics are right in like with what Swisher has always done. But unlike Aramis, Swisher is actually swinging at fewer pitches outside the strike zone than last year. At age 30, there should be no age-related concerns. From a statistical standpoint, I cannot find anything to suggest this lack of power will continue for much longer. As such, he makes for a good trade target, especially in AL-Only leagues, since he should not have been expected to generate significant value in mixed leagues to begin with.

One last point I want to make is that we simply never KNOW. It frustrates me as a fantasy owner, as a crystal ball would be quite helpful. Adam Dunn has been one of the most consistent power hitters in the game and now he sucks. Is it the “old player skills”, the league switch, the transition to a full-time DH? Maybe, maybe not. All we could do is look at a player’s history and play the percentages. We will be wrong a lot, and I will certainly be. However, the goal obviously is to be right more than wrong. Looking at a player’s track record and all of the other factors at play objectively will ultimately lead to reaching that goal.


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