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Recalibrating 50-grade power in 2019

Given the home run explosion, what does an “average” power hitter look like?

Philadelphia Phillies v Washington Nationals Photo by Scott Taetsch/Getty Images

Mansa Musa, sultan of the Mali Empire in the 14th century, may have been the richest person in human history. When he made his religious pilgrimage to Mecca, he distributed gold bars to all of the poor people he met along his journey— so much that he caused widespread inflation across Northern Africa for years thereafter.

MLB hitters have been distributing baseballs over outfield fences almost as charitably as Mansa Musa, with less economic devastation. However, there is a similar unintended consequence of inflation. If nearly everyone is a power hitter, what does an average power hitter look like?

Scouts often evaluate prospects using the 20-80 scale, in which 50 is average, 60 is one standard deviation above, 40 is one standard deviation below, etc. Given the home run spike across the league, 50-grade power hitters ought to have more home runs in 2019 than they did last year, and certainly much more than in offensively repressed eras like the 1970s. As a result, we have to calibrate mentally; 20 home runs in 2019 means less than 20 home runs in 2018 or 1972.

We’re not quite halfway through the season, but we have should have enough data to determine what each grade on the scouting scale should resemble. We could just take the MLB average home run rate for non-pitchers, which is about a dinger every 32 plate appearances. Over the course of a full season (600 plate appearances), that works out to about 19 home runs. The closest payer to the MLB average level is Cubs center fielder Albert Almora, who has seven in 225 plate appearances.

However, that isn’t exactly true to the intent of the scouting scale. A 50-grade tool is supposed to be average for a starter, not just the true statistical average including all of the backups and Quad-A guys. To find true 50-power, we have to filter out all the non-regulars, or at least as many as we can.

The easiest way to do this is just use all of the hitters qualifying for the batting title thus far. That requires about 230-240 plate appearances, depending on how many games each team has played. This seems too restrictive, though. It removes all but five catchers, as well as several players who became regulars after the beginning of the season, such as the RedsDerek Dietrich, or missed time due to injuries, like White Sox rookie Eloy Jiménez.

Using 200 plate appearances as the boundary grabs more of the players we’re looking for, including 13 catchers. It’s imperfect, but will have to suffice. Through Saturday’s action, our sample is 214 players, who average a home run every 25 plate appearances. This would yield 24 over a 600 plate appearance season, with a standard deviation of 11 home runs. In other words, every 11 homers above or below a 600 plate appearance projection of 24 is a full scouting grade. A 40-power hitter will hit 13 bombs, whereas a 60-power hitter will smack 35.

Here are the closest players to each of the scouting grades from 30-70, as well as the very top and bottom power hitters. If you want to view the full spreadsheet, click here.

Power grades based on HR

Name PA HR HR per 600 PA 20-80
Name PA HR HR per 600 PA 20-80
Gary Sanchez 235 23 59 81
Cody Bellinger 320 25 47 71
Mike Trout 331 22 40 64
Rowdy Tellez 238 14 35 60
Michael Chavis 245 12 29 55
Paul DeJong 326 13 24 50
Chris Taylor 232 7 18 45
Andrew Benintendi 327 7 13 40
Lorenzo Cain 331 4 7 35
Yolmer Sanchez 232 1 3 31
Billy Hamiton/Miguel Rojas --- 0 0 28

There are definitely some interesting names on this list. Yankees catcher Gary Sánchez is baseball’s premier power hitter right now. He’s on a 600 plate appearance pace for 59 home runs! He’ll never achieve that number, though, because he’ll probably fall about 100 plate appearances short. However, he could threaten Johnny Bench’s single-season record of 45 dingers by a catcher.

Mike Trout is the closest player in baseball to 65-power, which is funny because most of his other tools are 70-80! Unlike Sánchez, he’ll finish with closer to 700 plate appearances, so he should blow past his 40 home run projection.

The most average power hitter in baseball is Cardinals shortstop Paul DeJong. He hit the 50-power mark right on the nose, but there are actually ten players that achieved a score of 50 (avert your eyes, Phillies fans!):

The 50s

Name PA HR ISO HR/PA 600 20-80
Name PA HR ISO HR/PA 600 20-80
Byron Buxton 227 9 .261 24 50
Ian Desmond 252 10 .237 24 50
Bryce Harper 331 13 .214 24 50
Paul DeJong 326 13 .212 24 50
Brett Gardner 274 11 .211 24 50
Victor Robles 282 11 .194 23 50
Ramon Laureano 305 12 .184 24 50
Avisail Garcia 282 11 .182 23 50
Asdrubal Cabrera 275 11 .181 24 50
Rougned Odor 254 10 .174 24 50

Yes, Bryce Harper, he of the $330 million contract, has been a league-average power hitter thus far. Most likely, he’ll pick up the pace in the second half of the season. Even if he doesn’t, he’ll finish closer to 30 home runs because he gets so many plate appearances.

The players above are sorted by isolated slugging (ISO) for a reason. Power is about more than just home runs. Byron Buxton is among the league leaders in doubles, whereas Rougned Odor has provided very little offense outside of his ten homers. Is it fair to consider them equal as power hitters?

It might be more accurate to calculate power grades based on ISO. The average ISO of our 200 plate appearance regulars is .197 with a standard deviation of .067. Using ISO, here are the closest players to each of the scouting grades from 30-70, as well as the very top and bottom power hitters:

Power grades based on ISO

Name PA HR ISO HR/PA 600 20-80
Name PA HR ISO HR/PA 600 20-80
Christian Yelich 310 29 .406 56 81
Joc Pederson 244 20 .330 49 70
Mike Moustakas 300 22 .307 44 66
Nolan Arenado 331 19 .264 34 60
Clint Frazier 209 11 .230 32 55
Justin Smoak 261 12 .197 28 50
Jean Segura 290 7 .164 14 45
Yuli Gurriel 304 5 .131 10 40
Martin Maldonado 212 3 .095 8 35
Hanser Alberto 235 3 .067 8 30
Billy Hamilton 235 0 .053 0 28

Reigning NL MVP Christian Yelich takes over the top spot with 81-grade power. Given his high plate appearance total and the fact that he plays everyday, he may well fly past 56 home runs. At his current rate of playing time, he would match Roger Maris’ 61!

By this measure, Justin Smoak is the most average power hitter in baseball. He makes an excellent poster boy for power recalibration. Last year, he crushed 24 home runs in 594 plate appearances, which was a slightly above-average amount for the home run environment. If he matches that same number this year, he will be perfectly average (ignoring the fact that he’s currently injured). The same home run total is less impressive.

There are flaws with this methodology worth noting. Neither home runs nor ISO are adjusted for ballpark or quality of competition. Both Nolan Arenado and Matt Chapman scored a 60 on the ISO-based power grades, but the former plays in Colorado and the latter in Oakland. Therefore, Chapman has been the better true power hitter this year. Regardless, this data should give a decent idea of where we stand with MLB power in 2019.

Daniel R. Epstein is an elementary special education teacher and president of the Somerset County Education Association. In addition to BtBS, he writes at Tweets @depstein1983