As I mentioned at the conclusion of last week's article I would bring up an idea that a reader at DRaysBay brought to my attention a few months back. As I'm sure most of you know IsoSLG is intended to judge a player's total power, however, as the reader pointed out, in reality IsoSLG hurts players with low batting averages. The reader was normative rather than just critical and offered a solution, rather than subtracting batting average from slugging percentage why not divide slugging by batting average instead?
The thinking being that if a player is hitting .200 with a .400 slugging and he raises his average to .250 his slugging won't rise to .450 unless every hit was a single, the relationship is not linear as IsoSLG would have you believe, but rather proportional.
It's certainly an interesting proposition; consider the example of Curtis Granderson and Pat Burrell. Granderson hit .302/.361/.552 along with 23 homeruns this season, an IsoSLG of .250, Burrell meanwhile hit .256/.400/.502 with 30 homers and an IsoSLG of .246. Using the IsoSLG metric Granderson would appear to have more raw power, and yet Burrell's slugging is .05 points higher he's punished for the .046 differential in batting average.
Using ProP (proportionate power) Granderson's power rates at 1.82, Burrell's meanwhile at 1.96. Of course there are other statistics to take into account outside of just homeruns and extra base hits when talking power such as in this case Granderson's speed, and the ballparks they play in, but for now the only thing we're concerned with is the pure power numbers.
One could argue that Granderson is the better player, I'd accept that as fact, but keep in mind the idea is simply judging power, not the overall repertoire. A possible argument would be that players with high batting averages are punished for possessing better luck and contact skills, but that's simply not true, here are the holders of the top ten slots in batting average and their ProP compared to Burrell's:
C. Jones 1.79
H. Ramirez 1.69
Perhaps the only name I'd dispute had a better power season than Burrell would be David Ortiz, here are the comparisons:
Burrell .502 SLG 30 HR 26 2B 1.90 ProP .246 IsoSLG
Ortiz .621 SLG 35 HR 52 2B 1.87 ProP .289 IsoSLG
However the purpose of ProP is not to show what the power numbers are, nor what they should be, but rather what they could be given progression in areas like speed, contact, and luck attributes. Oritz takes advantage of his power while Burrell does not due to his weaker contact set.
Perhaps a more appropriate label for the statistic would be PotP, potential power, who are some of the players that possess ProPs over 2.0, here's the league wide assortment of players with at least 25 at-bats this season:
Red Sox - None
Yankees - Shelly Duncan (2.15), Alex Rodriguez (2.05)
Blue Jays -None
Orioles - J.R. House (2.36), Alberto Castillo (2.01)
Rays - Carlos Pena (2.22), Elijah Dukes (2.057), Raul Casanova (2.051)
Indians - None
Tigers - Marcus Thames (2.05)
Twins - None
White Sox - Jim Thome (2.04),
Royals - Jason Smith (2.37)
Angels - None
Mariners - None
Athletics - None
Rangers - Victor Diaz (2.24)
Phillies - Ryan Howard (2.18)
Mets - None
Braves - None
Marlins - None
Cubs - None
Brewers - Prince Fielder (2.15)
Cardinals - None
Astros - None
Reds - Adam Dunn (2.09)
Pirates - None
Diamondbacks - Tony Clark (2.05)
Rockies - None
Padres - Scott Hairston (2.24), Russell Branyan (2.16), Morgan Ensberg (2.15)
Dodgers - None
Giants - Barry Bonds (2.04)
It's likely a pure coincidence, but I can't help but wonder if the San Diego Padres' brass uses something similar to judge power potential, hence the additions of Hairston and Ensberg, of course it's likely nothing, but hey a man can dream that Paul DePodesta theorized the same.
Carlos Pena leads all batting title eligible players in ProP, not a surprise if you've seen Pena play, he has an uppercut swing and when he makes contact with the sweet spot the ball goes a long, long way, including a 458 foot shot and an average of 402.9 feet per Hit Tracker.
Alex Rodriguez would finish fifth and even though he lead the majors in homeruns it makes sense, remember this is power potential more so than power displayed, Rodriguez' power ceiling in terms of homeruns is just around the 54 he hit this year, 60 being the most I could see him hitting.