Mike Fontenot or why high ISO guys make the best bench players

ISO or Isolated Power is a very simple stat. Slugging Percentage minus Batting Average*. Say a player slugs at .600 and has a .300 batting average, that gives him an ISO of .300 (it also makes him one of the ten or so best hitters in all of MLB.) It also means that for every ten times up to bat he's going to generate three extra bases. That could be a homer, a triple and a double, or three doubles. Good power hitters are going to generate high ISOs almost by accident (or, more accurately, by the product of their being power hitters.) In fact, if you jump over to ESPN's stats page and check out their ISO (or as they call it ISOP) leaders, you'll see the top of the list populated with the guys you'd automatically associate as being the best power hitters in baseball. As you might guess, the highest ever to end a season belongs to Bonds in 2001 when his ISO was .536. Sosa, McGwire, Bonds and Babe Ruth all topped .400 at various points.

Now the numbers those guys throw up are just gaudy because they're sluggers and their slugging percentage is just going to be naturally high, and thus their ISO isn't going to tell you anything you don't already know. Where ISO becomes a cool little stat to measure players value is with bench players†. It's also why I really like Mike Fontenot, even given his status as a grinder, his mullet, his ties to LSU and Ryan Theriot.

An average ISO is .120, a "singles hitter" is going to have an ISO around .80

Fontenot's ISO on the year is .207 which is great for a bench player. Does this mean he's a great baseball player? No, and truth be told he should never start, but considering he can play the middle infield with some degree of competence AND hit for power in limited at bats means he actually has substantial value as a bench player.

Darryl Ward's is .229. This number is why Darryl Ward is still in baseball.

For some South Side perspective, Toby Hall's is .194

And just for my own personal amusement, Ryan Theriot's ISO is .56 and Reed Johnson's is a slightly-better-than-I-expected .116.

Like most stats for bench guys, ISO is flawed because the sample size is going to be really small, but the stat passes what I like to call the "crusty old baseball guy" test. When you sit down and think of the guys that your average"crusty old baseball guy" is likley to name if you ask them to name good power hitting bench guys, the guys that they name usually have higher ISOs. Be aware that this is horrible methodology.

*PECOTA uses a modified version which weighs Triples and Doubles equally, the logic being that a Triple is indicitive of a player applying speed to a double to get an extra base, and not actually a measure of any extra power, so PECOTA ISO numbers might be slightly lower. In general, players at the major league level for whom ISO actually matters (like my guys above) aren't going to be guys that hit you very many triples. Guys that come off the bench who are actually capable of hitting triples are guys you hope can walk or single then steal a base to get into scoring position. High ISO bench guys are guys whose main role on the team to hit pinch hit home runs....

Terry Crowley's lucky he's in fuckin baseball! We saw that Terry Crowley had the ability to sit on his ass for eight innings like any other fan the come up and break one open in the fuckin 9th! Terry Crowley's career ISO is only .125, but he had at least 3 seasons of +.170 ISO numbers.

†at the major league level, when projecting minor leaguers and prospects, ISO's value increases exponentially as it's one of the most important indicators of future performance on higher levels of baseball.