This article is part of our Collette Calls series.
Most of the United States is under a heatwave, at least in the western part of the country. I was podcasting with BaseballHQ's Ryan Bloomfield today who said the projected high in Oregon was 115, which is mind blowing considering it has been higher than 90 degrees maybe five days here in Charlotte this year. We typically see an annual spike in the offense as temperatures warm, but 2021 also offers us the additional wrinkle of the random enforcement of substances of the baseball after the league looked the other way for entirely too long. It is too early in the new world order to make any definitive statements on the impact of the sudden and harsh changes, but this graph from Rob Arthur at BP shows just how dramatic spin rates have been impacted:
The sticky stuff crackdown has produced just an absolutely bonkers reduction in spin rates across the league. We really don't have a good historical parallel for how low RPM will end up, but this change is going to cut K% and boost runs by a lot. https://t.co/c5ST8JF3t0 pic.twitter.com/k98ASf223q
— Rob Arthur (@No_Little_Plans) June 25, 2021
We are likely going to see a spike in offense in the coming weeks as the high spin stuff disappears and the thermostats continue to rise. As play begins June 27, we are indeed seeing a spike in offense when looking at the pitching numbers. The league-wide ERA in March/April was 3.99, and that jumped to 4.08 in May, and
Most of the United States is under a heatwave, at least in the western part of the country. I was podcasting with BaseballHQ's Ryan Bloomfield today who said the projected high in Oregon was 115, which is mind blowing considering it has been higher than 90 degrees maybe five days here in Charlotte this year. We typically see an annual spike in the offense as temperatures warm, but 2021 also offers us the additional wrinkle of the random enforcement of substances of the baseball after the league looked the other way for entirely too long. It is too early in the new world order to make any definitive statements on the impact of the sudden and harsh changes, but this graph from Rob Arthur at BP shows just how dramatic spin rates have been impacted:
The sticky stuff crackdown has produced just an absolutely bonkers reduction in spin rates across the league. We really don't have a good historical parallel for how low RPM will end up, but this change is going to cut K% and boost runs by a lot. https://t.co/c5ST8JF3t0 pic.twitter.com/k98ASf223q
— Rob Arthur (@No_Little_Plans) June 25, 2021
We are likely going to see a spike in offense in the coming weeks as the high spin stuff disappears and the thermostats continue to rise. As play begins June 27, we are indeed seeing a spike in offense when looking at the pitching numbers. The league-wide ERA in March/April was 3.99, and that jumped to 4.08 in May, and is 4.34 today. For proper context, we should look at how things have gone the last few full seasons and that data table is below:
Year | March/April | May | June |
|---|---|---|---|
2015 | 3.93 | 3.82 | 3.77 |
2016 | 3.98 | 4.18 | 4.44 |
2017 | 4.09 | 4.30 | 4.64 |
2018 | 4.12 | 4.05 | 4.05 |
2019 | 4.35 | 4.46 | 4.61 |
2021 | 3.99 | 4.08 | 4.34 |
2015 was an oddball year in that offense declined into summer, but 2021 is behaving very much like 2016, which makes sense as the juiced ball came into play 2017-2019. Even in 2018, offense slid back just a bit as well, but we traditionally see things rise month over month. This is why we should not look into 2021 monthly splits as anything more than a mostly normal progression of data. If we change the table to show the percentage change month over month, we see just how closely the May to June spikes in 2016 and 2021 are with one another. We also see that we have never seen a month-over-month change in offense during the first half of a season in recent memory that we've seen as May became June:
Year | March/April to May | May to June |
|---|---|---|
2015 | -3% | -1% |
2016 | 5% | 6% |
2017 | 5% | 8% |
2018 | -2% | 0% |
2019 | 3% | 3% |
2021 | 2% | 6% |
The story inside the story appears when we split the numbers between relievers and staters. Relief pitching, by its nature, is a volatile group and we have seen some crazy things in the last few years but nothing as crazy as what happened to bullpen ERAs as May became June in the 2017 season:
Year | March/April to May | May to June |
|---|---|---|
2015 | -1% | -5% |
2016 | 7% | 4% |
2017 | -9% | 16% |
2018 | -3% | 1% |
2019 | 2% | 4% |
2021 | 6% | 3% |
That season, bullpens opened the season with a 4.18 ERA, and lowered it to 3.18 in May before it jumped to 4.42 in June. This season, bullpens opened up with a 3.93 ERA, which rose to 4.15 in May, and 4.26 in June. Again, nothing out of the ordinary and far from a wild swing of outcomes, which is surprising given the volume of turnover we have seen in bullpens this year due to injury. The same cannot be said for starting pitchers; their table is below:
Year | March/April to May | May to June |
|---|---|---|
2015 | -4% | 0% |
2016 | 4% | 7% |
2017 | 14% | 4% |
2018 | -1% | 0% |
2019 | 3% | 2% |
2021 | 0% | 9% |
That craziness of 2017 shows up here too, but note how March, April and May had no change, and we have seen a near double-digit change (9.47 percent to be exact) in June as the collective starting pitcher ERA has risen from 4.02 in May to 4.40 and counting this month. There are nine rotations with team ERAs of 5.00 or higher in June:
- Cleveland - 5.00
- Colorado - 5.07
- Boston - 5.14
- Pittsburgh - 5.50
- St. Louis - 6.11
- Minnesota - 6.25
- Arizona - 6.54
- Kansas City - 6.88
- Baltimore - 7.59
Baltimore's rotation is such a mess that if the Mets took their June rotation ERA (2.52) and tripled it, it still would not be as high as Baltimore's figure in June. The Mets, Nationals and Astros each have rotation ERAs less than 3.00 this month. To revert back to the first chart, this is what the league-wide ERA's look like for starting pitchers in recent years:
Year | March/April | May | June |
|---|---|---|---|
2015 | 4.15 | 3.97 | 3.98 |
2016 | 4.10 | 4.27 | 4.59 |
2017 | 4.04 | 4.59 | 4.76 |
2018 | 4.20 | 4.15 | 4.13 |
2019 | 4.33 | 4.46 | 4.57 |
2021 | 4.03 | 4.02 | 4.40 |
The 4.40 mark this month is the fourth highest we have seen in the last six seasons for June despite the current May to June being the highest change between those two months in recent seasons. The new spike in offense appears to be more on the starters than the relievers and that may be a combination of the change in how they can manipulate the baseball as much as it is them hitting the wall as they resume normal workloads after an abnormal season.
We expected a learning curve this season as pitchers adjusted to the different workload, but the combination of workload resumption and baseball manipulation appears to be having the desired effect of increasing offense in the league this season even if those numbers still are not to the levels they were the previous three full seasons. Pitchers will need time to adjust to the new baseball and some high-profile names are struggling to do so. As fantasy players, we should look for a continued upswing in overall offense in the near term, but the sport always finds a way to adjust, so I would be surprised to see this as the new norm for the rest of 2021.
