The Mets and the new home run boom

Major League Baseball is in the midst of another home run surge, returning to and even surpassing 2017’s record-setting pace after a dip in 2018. A full 14.4% of balls hit in the air are leaving the park so far this year, up from 13.7% in 2017. The jump is even more remarkable when you consider that we are still just a few weeks into the season and most games are being played in well-below-average temperatures. Indeed, if you look at just March and April, 2017 saw a home run per fly ball ratio of 12.8%—a record by a long shot at the time, one that is now being left in the dust.

Not only are more hits going over the wall, everything is being hit harder. A 37% hard-hit rate, per FanGraphs, is a record for this early in the season by far, and alas, cannot be entirely attributed to Pete Alonso. Whether you’re a juiced-ball truther, a launch angle evangelist, or something else entirely, there’s no question something is different and the Mets are in the thick of it.

Offensively, the Mets have seen an uptick in their home run per fly ball ratio from their previous record of 13.6% set in 2016 to 14.1% this season. That is all the more remarkable considering that chilly April weather is not conducive to long balls at Citi Field. Their hard-hit rate has also jumped over three percentage points from the previous record, also set in 2016, to 36.7%.

Besides the inimitable Pete Alonso, several Mets are going long well above league average rates. Brandon Nimmo, J.D. Davis, and Juan Lagares are all seeing at least a quarter of their fly balls leave the yard. Of that group, only Davis has seen that kind of power previously, in his brief 2017 appearance. Nimmo in particular is seeing a huge spike to his hard-hit rate, all the more notable given his slow start.

But the home run giveth and the home run taketh away, and Mets pitching has taken a significant hit. Their combined 15.6% home run rate is up from 2017’s record 14.9%, but even more alarming is a hard hit rate of over 40%, up a full 8% from 2016’s previous high. With a sweaty Queens summer right around the corner, these are the kinds of numbers that will keep Dave Eiland up at night.

Leading the charge in this trend, unfortunately, is Jacob deGrom who is giving up hard contact well over 50% of the time, double his previous career worst, and his 22.7% home run per fly ball rate dwarfs his previous 16.1% record. Noah Syndergaard is in a similar boat, though not to the same extent.

The relief corps is particularly burned by the home run ball, with nearly all of the recent offseason’s additions suffering. Jeurys Familia, Justin Wilson, and Luis Avilan are all looking at huge leaps in their home run rates. Robert Gsellman is also giving up exceptionally hard contact, as is Edwin Diaz, although it’s less of a concern for the latter as he so rarely gives up any contact at all.

While these are all early trends and small samples, they map closely to the larger league numbers, which point to a significant difference in how the ball is moving this year, to an even more extreme degree than was seen in the 2016-17 home run boom. In particular, if the Mets are going to compete all season, it’s essential that their elite arms adjust to the new offensive environment. Because with big boy Pete Alonso leading the pack, they are going to make some noise.