The Case for McGwire

Just watching another one go high and deep.

Mark McGwire belongs in the Hall of Fame. Here, I will look into a less obvious question: Was Mark McGwire the best right-handed power hitter in baseball history?

This question is not about his overall hitting skills. McGwire hit .263 for his career, putting him right around the historical average. He beat .300 over a full season only once, and he hit .231, .235 and .201 in consecutive years from 1989 to 1991. During his 15 years in the league he managed just 785 singles, about the number that Ichiro hits in a little over four seasons. He struck out. A lot. He whiffed in over a quarter of his at bats, piling up nearly as many K’s as hits over his career. His strikeout rate accelerated toward the end of his career, and in his last season, in 2001, he struck out more times than he reached base.

McGwire’s last season was remarkable in how it represented the extrapolation of his skills, taken to an absurd extreme. He came to the plate 364 times with this line: 118 strikeouts, 56 walks, 56 hits, and 29 home runs. He hit 29 homers but only four doubles that season, after hitting 32 homers with eight doubles the previous year (of course, no triples in either season—he hit only six his entire career, four of those in 1987, his rookie year). Even with a .187 batting average in 2001, he still got on base well over 30 percent of the time and managed an .808 OPS. FanGraphs actually marks him as a few runs above average with the bat that season.

The A’s did not have a fashion consultant on their payroll.

Clearly, Mark McGwire was not a great singles hitter. He was not a doubles hitter, and he most definitely was not a triples hitter. McGwire was a home run hitter. He set the rookie record with 49 for the Oakland A’s in 1987. He topped 40 again in 1992, and in 1995 hit 39 in 104 games, a full-season pace of 61. And then, from 1996 through 1999, he put on the greatest fireworks show in history. Not only did he shatter Roger Maris’s 37-year-old single-season record of 61 homers, he averaged 61 homers over those four seasons, despite missing 54 total games and walking an average of 128 times. He ended his career with 583 home runs, which currently places him tied for eighth on the career list. And he hit all of those home runs while playing for Oakland and St. Louis, in home parks that are not particularly kind to home run hitters.

While McGwire did hit a lot of home runs over his career, Hank Aaron (755), Willie Mays (660), Sammy Sosa (609), and Frank Robinson (586) were all right-handed hitters, and all hit more. In the next couple of years, Alex Rodriguez (583) and Manny Ramirez (546) will pass him easily. If we look at a traditional rate number for power hitting, career slugging percentage, McGwire ranks ninth all-time, and again there are four right-handers ahead of him: Albert Pujols, Jimmie Foxx, Hank Greenberg, and Manny Ramirez. How, then, is McGwire the best right-handed power hitter in baseball history?

Once upon a time, you could be tubby and also be the best slugger in history.

McGwire certainly hit for power in great quantity, but when we look at quantity alone, he does not appear to rank at the top. Due to injuries and retirement after his age-37 season, he had a relatively short career—only 7,660 plate appearances, compared with 13,940 for Aaron, 12,493 for Mays, 9,896 for Sosa and 11,743 for Robinson. He walked at a significantly higher rate than any of those four, further whittling his chances to slam his home runs. And his low batting average pulled down his slugging percentage. Rather than career home runs or career slugging percentage, two other statistics reveal McGwire’s true power prowess: at bats per home run (AB/HR) and isolated slugging percentage (ISO).

AB/HR measures the rate at which a player hits home runs. It is simply a player’s at bats divided by his home runs. When a player walks, he has no opportunity to put the bat on the ball. This is sometimes by choice and sometimes because he receives nothing hittable. Discarding walks and using only at bats, rather than plate appearances, gives us a better idea of how good he was at driving the ball out of the park. A lower number is better, because it indicates that the player hits home runs more often. The other statistic, ISO, is slugging percentage with the singles taken out—a measure of pure power. To calculate it, subtract singles from total bases and divide by at bats. Think of ISO as the number of extra bases (that is, bases past first base, so a double is one extra base, a triple two, and a home run three) a player gains, on average, per at bat. A player with an ISO of .100 gets an extra base once every ten at bats. A player with an ISO of .250 gets an extra base once every four at bats. Below is a table with the best five career marks for AB/HR and ISO.

In these pure power statistics, McGwire soars above the right-handed competition. No right-hander hit home runs at anywhere near the pace he did over his career. As for ISO, the rate at which he racked up extra bases, Pujols is the nearest right-hander and lags 30 points behind. But what if McGwire’s short career benefited him here? What if he retired early enough to avoid a slow decline that would have brought down his overall rates? To determine how McGwire’s peak compares to other sluggers, here are the top 15 single-season marks for AB/HR and ISO.

Now things are looking pretty solid for McGwire. The only other righty that makes it onto either list is Sammy Sosa, for his incredible 2001 season when he hit 64 home runs, 5 triples, and 34 doubles. Apart from the high single-season and career home run totals, though, Sosa’s power hitting ability was nowhere close to McGwire’s. Both his career slugging and ISO were more than 50 points lower than McGwire’s, he struck out just as often while walking half as often, and he hit about the same number of career home runs in around 2,600 more at bats.

Jimmie Foxx: Awesome name, 534 career home runs.

Other batters that may have a case for best right-handed slugger ever include Ralph Kiner, who bashed 369 homers in just a 10-year career, Hank Greenberg, who slugged .605 over his career with a .292 ISO, and Jimmie Foxx, who in the 1930s had seasons of 58, 50, 48, and 44 home runs and had a career .609 slugging percentage. Foxx may have been the best relative to his peers, as he played in an era when home run power was scarce, but we are investigating absolute rather than relative greatness. And none of these players were able to hit home runs or pick up extra bases at quite the rate that McGwire did. Current players Alex Rodriguez, Albert Pujols, and Manny Ramirez are all great power hitters as well. That trio will rank near the top of the right-handed slugging heap when they are done, but so far they also have not equaled McGwire’s rates, and all still have a decline phase ahead. Finally, Aaron, Mays, and Robinson were fantastic overall hitters and had great power, but they reached their huge career home run totals through longevity. Again, none hit for the fences or for extra bases at quite the rate that McGwire did, during career or peak.

In terms of pure, unadulterated power—home runs and extra bases—Ruth, Bonds, and McGwire were the greatest in history. McGwire is the righty of the trio; thus, he was the best right-handed power hitter in baseball history.