Alex Rodriguez's power on contact

Thursday's blog titled "Did A-Rod really gain an edge from PEDs" stirred up some heated debate in the comments section. On Twitter, Paul Sporer asked about Alex Rodriguez's isolated power on contact, the Joe Sheehan stat used in the chart listed in that piece.

Remember, isolated power is slugging percentage minus batting average -- it takes singles out of the equation. By removing strikeouts, we're then checking A-Rod's power only when he makes contact.

1996: .330

1997: .236

1998: .303

1999: .384

2000: .372

2001: .383

2002: .402

2003: .380

2004: .289

2005: .376

2006: .307

2007: .417

2008: .351

2009: .314

2010: .290

2011: .235

2012: .210

Well, one thing, if Rodriguez has been using PEDs in recent seasons, they haven't helped. His isn't a Barry Bonds-like career path, that's for sure, but a rather conventional downward arc beginning in his mid-30s. It's interesting to note that Rodriguez's ISO/con didn't really increase all that much from his final two seasons in Seattle after he joined Texas in 2001, when he said he used PEDs -- even though he moved into a better hitter's park in Texas (the Mariners had moved into Safeco midway through the 1999 season).

We can only speculate about the dips and rises. In 2004, he joined the Yankees. Maybe he did stop PEDs, as he claimed, or maybe he just felt more pressure playing in New York ... and fell from 47 home runs and 83 extra-base hits to 36 and 62. He had a big spike in 2007 when he went from 35 home runs to 54. Did he start using PEDs? Make adjustments at the plate? Just have a great year?

We also don't know the typical variance in ISO/con. What's normal and not normal for an elite slugger? Here, let's look at Jim Thome, a guy with 612 home runs and whom everyone believes was clean:

1994: .346

1995: .324

1996: .418

1997: .414

1998: .428

1999: .402

2000: .378

2001: .513

2002: .525

2003: .447

2004: .429

2005: .209 (injured)

2006: .443

2007: .416

2008: .365

2009: .351

2010: .490

2011: .333

Well ... certainly a different arc than A-Rod (and also: Man, did Thome have some serious power or what?). A mammoth peak in 2001 and 2002 (when he was 30 and 31 years old) but otherwise pretty steady until he started getting old. Anyway, this proves nothing, other than Thome had more power than A-Rod, but Thome is also one of the all-time Three True Outcome kings (home run, walk or strikeout), so he's a pretty unique guy to compare to anybody.

You could do this all day with various players -- Willie Mays, Hank Aaron, Mike Schmidt, Miguel Cabrera ... Barry Bonds. Bonds would be a fun one. From 1958 to 1960, Mays averaged 31 home runs per year. From 1962 to 1965 he averaged 47. Did he start juicing? Probably not. Players change, conditions change, ballparks change. You can look at the numbers but the numbers don't always us provide an answer.