No one does a better job of having his fly balls end up in the stands than Jim Thome.

In last week’s episode of Statistics 101, I looked at pitchers who were posting historically low ratios of home runs allowed per fly ball (HR/FB%), including the Padres’ duo of Chris Young and Jake Peavy, who, along with Brad Penny, have allowed less than three percent of the fly balls hit against them to leave the ballpark. This week, I’ll be looking at the players on the opposite end of the spectrum: hitters whose fly balls are leaving the yard at unprecedented rates.

What would happen if Young (HR/FB% of 2.5 percent) faced Jim Thome (HR/FB% of 32 percent)? I wish we could find out. Thome leads the major leagues in home run rate, crushing 16 home runs on just 50 fly balls. Thome has a groundball ratio of 1.52 and has played just 73 games, but his ability to drive the ball out of the park when he elevates it has helped to salvage his season. Not surprisingly, Ryan Howard ranks second in the major leagues with a HR/FB% of 30.7%, and Alex Rodriguez ranks third at 29.6%. The Reds’ Adam Dunn and the Devil Rays’ Carlos Pena round out the top five hitters. Perhaps the most amazing thing about A-Rod’s amazing season: his line drive percentage is just 17%, which means his batting average could theoretically go up!

While looking at the historical leaderboard for pitchers, I discovered that pitchers like Young and Penny were outperforming even the league leaders from previous seasons, and it seemed reasonable to expect that their HR/FB% numbers would normalize to the range of leaders in previous seasons. The hitting leaderboard does not show the same over-performance: this year’s hitters are in line with historical numbers. In 2006, Howard led the major leagues with an astonishing 39.5 percent HR/FB, Travis Hafner ranked second at 30.2 percent, and Thome ranked third at 27.8%. The most astonishing performance was Jacque Jones, who ranked fifth with a ratio of 25.5% and a groundball ratio of 2.19. If you think that combination is sustainable, check his 2007 numbers. Perhaps that is a word of caution for Jim Thome in 2007, who also has a very high groundball ratio for a player on the HR/FB% leaderboard.

In 2005, the leaders in converting fly balls to home runs posted slightly lower numbers. Manny Ramirez led the way with a ratio of 26.6%, A-Rod finished second at 25.8%, and Andruw Jones ranked third at 25.2%. Preston Wilson ranked fifth with another high groundball ratio (1.89) and was never heard from again. In 2004, Barry Bonds led the league with a HR/FB% of 29, and Sammy Sosa finished second with a ratio of 26.7%. None of the top hitters had an extreme groundball ratio, but Sosa fell off the map anyway.

In 2003, the top two hitters were Thome (30.3%) and Bonds (29.6%) again. Richie Sexson ranked third at 29.2%, and his groundball ratio of 1.40 was the highest of any player in the top 10. He was injured the next season, so it wouldn’t be fair to blame his groundball tendencies for his poor 2004 season. In 2002, Thome led the league again, this time at 35.4%, and Sosa ranked second at 31.2%. The highest groundball ratio belonged to Shawn Green (1.66) and he dropped from 42 home runs to 19 the following season.

So what does all this mean? A consistently high HR/FB% seems to be a much more consistent skill for hitters than it is for pitchers. Anyone who has watched Jim Thome’s massive uppercut could probably guess that, and so could anyone who has seen A-Rod’s lightning-quick bat (2006 not necessarily withstanding). At the same time, it is dangerous to be near the top of this list when you start hitting more balls on the ground: this probably signals a desperate hitter still swinging for the fences but getting the ball in the air less frequently. Based on their current 2007 numbers, Thome appears to be the only top slugger in serious jeopardy, but you might also want to keep an eye on Chipper Jones (18.6% HR/FB and 1.29 G/F) and Jhonny Peralta (15.1% HR/FB and 1.52 G/F) just in case.

Questions and comments can be sent to John at johnfranco@sportsgrumblings.com