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“Just Enough” Home Run Leaders: Impending Power Decline?

ESPN Home Run Tracker (formerly HitTrackerOnline) is a great resource I feel has been very underutilized. For those not familiar with the site, it measures the distance of every home run hit and then categorizes them based on how far past the fence they flew. Last year I studied previous seasons to see what kind of predictive value home run distances have. I found that the hitters who hit a high percentage of “Just Enough” home runs (league average from 2006 was 27%, no updated data available) saw their HR/FB ratios decline by 21% the following year, versus 11% for the hitters who had hit the lowest percentage of Just Enough home runs. The process passes the sniff test as well, so below are the five hitters with the highest percentage of Just Enough home runs, while hitting a minimum of 10 home runs.

Ryan Roberts at the top of this list should not be too surprising. Projected by ZiPS to hit just 9 home runs in 408 at-bats, he already has 10 in a little more than half that. He has only accumulated 608 at-bats at the Major League level, so he does not have enough history to confidently call this a fluke. Of course, he has never shown this kind of power in the minors and he is already 30 years old. Add up all these warning signs, and it is unlikely this power surge continues at this pace.

After hitting just 3 home runs over 411 at-bats during his time at Triple-A in 2009, Drew Stubbs proceeded to hit 30 home runs with the Reds over 594 at-bats from that year through 2010. Natural, most questioned whether this new found power was a fluke or a legit power spike. This year, he has posted an identical HR/FB ratio, but his Just Enough percentage of 60% is dramatically higher than last year’s 18%. If his FB% remains down, I would bet on his HR pace declining. However, he could potentially keep it up if he gets that FB% back in the high 30% range.

Danny Espinosa launched his 13th homer yesterday, but of course that was not included in the above table. Besides the high Just Enough percentage, another warning sign for his power is his low LD%. It might seem strange to look at a low LD% and predict worse power to come, but you have to think his 11.5% LD% will rise, and when it does, it will come at the expense of at least some fly balls. So even though it should be good for his batting average, it will lead to fewer fly balls, and all else equal, fewer home runs.

Miguel Cabrera also homered yesterday, which is already making the predictive power of this list look bad. Last year, Miggy’s Just Enough percentage was just 26%, slightly less than half the mark he has posted this year. Coming into yesterday’s game, he had already posted his lowest HR/FB ratio since 2006, though it still remained in the high teens. I am not sure I would predict any imminent decline here, though it is worth monitoring these Just Enough home runs from him.

Ryan Howard is tied for the lead in Just Enough home runs this year. Last year, his Just Enough percentage was also rather high at 42%. His HR/FB ratio is already on a 3-year decline, but a fly ball rate at its highest since 2007 has led to a slight rebound in ISO. After hitting 12 homers against lefties last year, he has 0 in 86 at-bats this season. Many have predicted a sustained decline for Howard and his home run power turning into doubles power and complete lack of punch against lefties this season is making the pessimists look quite good. The days of 40+ home runs look to be far back in the rearview mirror.