As spring gradually shows up here in the twilight of April, regular baseball weather has finally started to sprout upon us. Much was made about this odd month and its temperature and precipitation, which was mainly noticed through the postponements and delays that came in at an insanely high rate.
The large amount of postponements was pointed out in a piece over at AccuWeather a few days ago.
When the game between the Chicago Cubs and St. Louis Cardinals was postponed on April 18 in Chicago, it marked the 25th postponement of the young season. The 25 postponements in April tied a record previously established in 2007, according to the Associated Press.
Two games on Tuesday were postponed due to rain, one between the Baltimore Orioles and Tampa Bay Rays in Baltimore and the other between the Pittsburgh Pirates and the Detroit Tigers in Pittsburgh. This brings the number of postponements in April up to 28.
Also noticed was the affect the weather had on the actual game itself. Just to start off by showing things in a general term, run scoring in Major League Baseball for April of 2018 was... well, actually not that insane, considering monthly league-average wOBA is pretty volatile in a small range.
But this isn’t exactly the weird part. Look deeper and you’ll find that baseballs this month have been hit harder than ever.
And like most of Major League Baseball, the Royals have been hitting the ball harder than usual, putting up an average exit velocity of 88.4 MPH, which ranks in the top half of baseball. It’s early, but it’s a substantial raise from their 2016 average of 87.5 MPH and 2017 average of 87.0 MPH. It isn’t a stretch at all to say the Royals have put together a team better suited for harder-hit batted balls, as they rank third in all of baseball in Hard Hit%. But for some reason, the results aren’t showing for this offense.
All it takes is a brief look of the numbers to figure out the Royals offense has not been good this year. They rank 30th in runs scored, 28th in ISO, and 24 in wRC+ as a team. But if you look solely off the batted ball metrics, you would think the Royals’ bats haven’t been all that terrible to start 2018. Put those two together, and you’ll find that the Royals have had one of the more “unluckier” offenses early this year.
Five Biggest xwOBA-wOBA Differentials for Hitters
The good news with the Royals stops there though. Flip things to the other side of the spectrum and you’ll see that the over-performing starting rotation has been extremely lucky.
Five Biggest xwOBA-wOBA Differentials for Starting Pitchers
So in this unusually wide separation between batted ball results and actual results to start 2018, it’s fairly easy to say the Royals have been the team most affected by this. And this separation we are currently seeing may be the largest in recorded history.
The numbers are quite staggering in fact. The xwOBA-wOBA differential so far for April of 2018 has been .025 (.332-.305). The next largest differential was .013 (.297-.310) in June of 2015. This probably disapproves any other theories as to why this month has been such an outlier for offensive production, say a change in the baseball.
This brings me to the main point I wanted to get across in this piece. It isn’t anything new that colder temperatures hampers the production of offense in baseball. The colder the temperature, the harder it is to get hits fall, flyballs to leave the ballpark, etc. This April has undoubtedly been one of the colder April’s we’ve seen in recent history and these early numbers are being skewed at a higher level than we may have ever seen, or at least in recorded history.
The teams that take the biggest effect from this are those of which are in the midwest, as four of the five biggest xwOBA-wOBA differentials have come from what you could classify as teams located in the midwest.
This probably won’t last much longer though. With April coming to a conclusion and the temperatures starting to rise as spring matures into summer, we’ll likely see the numbers go back to their usual form. This could mean that the Royals offense might actually start scoring a little bit more (though they’re still a below-average offense) and the starting pitching will most likely take a deep dive downwards.