Perusing around on FanGraphs recently added + Stats leaderboard, I came across some equally interesting and hilarious stats. Looking at the stat ISO+ (measures a team’s isolated average relative to the rest of the league in that season) and filing it down to every team since 1871, something stood out. I saw the 10 worst teams in ISO+ and their respective seasons. For maximum hilarity, I’ll just start out by saying what seasons those 10 teams played in. It went in the order of: 1872, 1872, 1873, 1875, 1872, 1872, 1884, 1884, 1871, 2019, 1871.
Before I dive into the glaring outlier there, I’ll start off by saying that these numbers probably aren’t 100 percent filled with context and accuracy. To start out, who knows the level of accuracy in stat-keeping 150 years ago. And also, my guess is there was a wide separation in ballpark factors compared to now, causing the ISO+ numbers to severely inflate and deflate for teams at the top and the bottom. The separation in ISO+ between the top team and the bottom team in 1871 was 106 percent. In 2018, it was 64 percent. As you can see, the gap has closed throughout the years.
Nonetheless, that outlier is still hilarious, and it does represent statistical significance. Some of you may have already guessed this team, some of you are still waiting on the edge of your seats. They are the 2019 Miami Marlins, who currently hold the worst ISO in the major leagues, standing at .086. The next worst team this season so far has been the White Sox, who still stand far ahead of them at .104, followed by the Blue Jays and Giants at .124 and .128.
For further context, the Marlins are pacing to have the worst ISO+ of not just since the beginning of the 21st century, but the 20th century too. You would have to go all the way back to 1884 for them to move down the leaderboard, as both the 1884 Apostles and 1884 Nationals are worse them. The Marlins are on pace to have the ninth worst ISO+ in the long history of baseball.
To make matters seem worse, they are also trending in the wrong direction. In April, their ISO+ was bad, but not historically bad— 40 percent below league average, just one percent under the Blue Jays. But in May, they’re a whopping 81 percent below league average. The next closest team is the White Sox, who are marked at 55 percent below. The worst ISO+ by a team in a month last season was 48 by the Rays in June, followed by the Marlins, once again, in September at 49.
ISO+ By Team In May
Looking at how the got here through Statcast, they don’t really hit a lot of fly balls (second to last in the majors) and they don’t hit fly balls very well (worst wOBA in the majors).
It’ll be interesting to see just how bad their power numbers as a team stand once the season is complete. But from the early season indicators, their lineup of past-prime veterans and triple-A hitters seems like it has a legit shot to finish as one of the worst power-hitting teams of all time.