Has Nola Just Been Unlucky?
Despite the shifts in the location of his fastballs and his knuckle-curve, there are two main statistics that may explain Nola’s recent struggles best. BABPIP measures the batting average of balls in play and usually stabilizes around .300. For a pitcher, a BABIP over that value is typically deemed as bad luck, whereas a value under .300 is regarded as luck.
LOB% measures the percentage of base runners stranded by a pitcher. In 2019, the league-average LOB% currently sits at 72.2%. Again, for a given pitcher, values above or below suggest luck may be a factor in the rest of their statistics.
If we compare Nola’s statistics from before and after his August 25 start in Miami, we can see that his BABIP and LOB% are drastically different. His BABIP jumped from .287 to .316, whereas his LOB% decreased from 79.6% to 63.8%.
It seems that luck played a role in Nola’s 2019 season prior to this recent stretch. He was benefiting from a BABIP lower than league average and a LOB% higher than league average. They both helped keep his ERA below his FIP, giving him decent overall numbers for the majority of the season.
Since August 25, however, his BABIP and LOB% have swung in opposite directions. This has thus induced the discrepancy between his ERA and FIP to flip, as well, with the former rising above the latter.
What does that mean on the whole? Well, BABIP and LOB% are two metrics that typically fluctuate over the course of a season, and ultimately stabilize at values that explain a pitcher’s true performance. A pitcher can outdo underlying metrics for stretches, but will likely also receive some bad luck at some point, too. Perhaps Nola is just in the middle of one of those unlucky stretches.