Baseball HQ: Power buyer's guide

The following is a group of players for whom it is not readily apparent whether their current power output is for real or a fluke. We pass judgment...

Alex Gonzalez (SS, Reds) is in the midst of a comeback season. At age 30, he's hit 13 HR in 315 AB with a decent .444 slugging and 128 PX (power skills as indexed to league average). Gonzalez's other performance indicators (walk rate, contact rate, batting-eye ratio) are in line with historical levels, suggesting that his power resurgence is not a fluke. A 44 percent fly-ball rate, which nearly matches his level in three of the past four seasons, confirms that supposition. We project Gonzalez for another 8 HR in 224 AB -- not bad from the typically light-hitting SS position.

• Ken Griffey Jr. (RF, Reds) is defying the odds, not only by staying healthy, but also by reversing declines in his fly-ball rate and power index. From 2004-06, Griffey's fly-ball rates went from 47 to 44 to 43, respectively, while his power index went from 160 to 168 to 130. Contrast that with Griffey's current 50 percent fly-ball rate and 153 power index, and it looks like Griffey has drunk from the fountain of youth. However, over the past 31 days, Griffey has hit just 5 home runs (of his 24 total) with a 132 PX -- a power level about equal to what we project the rest of the season (138 power index, 12 homers in 169 at-bats).