In my early preseason draft preparations, I have been reading quite a bit about last year’s home run explosion in major league baseball. This got me curious to look in greater depth at changes in the game and how much last year’s stats were an outlier (or not). In this post, I will explore trends from the starting pitching angle, with a future post to be devoted to hitting.

First up, I got to wondering about starting pitching usage and the implications it might have for Rotisserie baseball. As I have been scanning early projections on pitchers I have noticed that most starters with any kind of major league track record are being penciled in for 180+ innings. That seemed fishy to me since there appear to be fewer workhorses with each passing year. So I headed on over to fangraphs.com and baseball-reference.com to crunch some numbers and see if the data supported my intuition.

One data point that I believe is given insufficient attention by fantasy baseball players is the number of starting pitchers who pitch a complete season’s worth of innings at the major league level each year. First and second year pitchers tend to be on innings limits, as are players coming back from injury, and even healthy veterans are getting removed from games earlier, reducing their ability to rack up innings pitched. Indeed, the number of pitchers who threw enough innings to qualify for the ERA title fell to a modern low last year.

The data is a bit noisy, but it demonstrates that 2016 produced a 17-year low in the number of pitchers who reached the 162 innings threshold, furthering a decline that began in 2015. It should be noted that 162 innings is not a particularly onerous threshold; if a pitcher only averages 5 2/3 IP per start he can still qualify with 29 games started, allowing him to miss 3 turns through the rotation.

What if we beefed up the threshold a bit and started looking for true workhorses? A 190 IP threshold is tougher to reach but can still be accomplished by averaging 6 IP per game while making 32 starts, answering the bell every 5th game of the season. The results are quite dramatic.

For most of the past two decades, the number of workhorse starters per season has ranged from the 50s to low 60s. Yet 2015 saw this number plummet to 36 and 2016 witnessed an even further decline to 30. Basically, the number of workhorse starters has been cut nearly in half in recent years. While I think most fantasy players intuitively understand the decline in starting pitcher innings totals, I am not sure we have fully adjusted to the extent of this change. Pitching durability is a skill and an increasingly rare one at that. As we prepare our player projections we should be as methodical about producing a realistic IP total as we are about forecasting rate stats like ERA and WHIP.

Diving deeper into the pitching data, we can start to understand *why* big innings totals by starting pitchers have declined. Let’s take a look at the length of an average MLB start over the years.

Here we find a statistic that was remarkably stable from 1999-2015, always landing between 5.8 and 6.0 innings per start. However, 2016 witnessed a new low, with the average MLB start lasting just 5.6 innings. This may not appear to be a huge change, but if the trend continues we might begin to see more dramatic declines in Win totals by starting pitchers. As the next chart shows, this decline may already be underway.

In 2016, starting pitcher wins (as a percentage of games started) reached a modern low at 33.5%. This is down slightly from the 35% or so figure that we have generally witnessed in recent times. This is not a large enough difference to substantially impact the fantasy game, as it reduces the average pitcher’s win total by only half a win over a 32 start season, but it bears watching in the coming years.

While starting pitcher wins have declined somewhat the past few years, the percentage of wins accumulated by the top starting pitchers has inched up slightly:

In 2016, the top 20 win leaders in MLB accounted for 21.0% of all starting pitcher wins. This results from a steady, modest increase in the percentage of wins accumulated by the top starting pitchers since the 2013 season, which saw the top 20 racking up 19.1% of all starter wins. In short, wins by starting pitchers are declining slightly and they are being modestly distributed upwards toward the top pitchers.

So, what are the takeaways of these trends for the fantasy game? I would argue that they demonstrate top-tier starting pitchers, especially those who have demonstrated proven durability, have gained value relative to the average starting pitcher. If the changes in the starting pitcher environment continue or even just plateau in 2017, you might gain an edge by going an extra dollar or two for highly skilled workhorses. Also, if you play in deeper leagues (e.g., AL- or NL-only), when it comes to rostering your last pitcher you may want to consider selecting a talented middle relief or set-up man over a run-of-the-mill starter (the inverse of declining starter wins is an increase in relief wins; as the win total gap between a mediocre starting pitcher and a quality reliever narrows, it becomes more enticing to select the reliever who is likelier to contribute positive value to your team’s ERA and WHIP).

The key unknown is whether 2016 represents the acceleration of a trend that will continue into 2017 and beyond or whether it represents something of an outlier. Will MLB front offices and managers continue to give earlier hooks to their starting pitchers? Will MLB teams continue to utilize more young pitchers on cheap contracts (and on strict innings limits) in their rotations? Will MLB get better at limiting major arm injuries to pitchers, thus allowing more pitchers to throw a complete season’s worth of innings? No one can answer this definitively ahead of time, but most of what I read about how MLB teams view pitcher usage leads me to believe that it is more likely than not that 2016 is *not *an outlier. I think the scales are tilting such that top-tier starters and non-closing relievers are becoming more valuable in our game, relative to starting pitchers with either shaky skills or uncertain durability. If my leaguemates do not recognize these trends I will likely be owning more shares of the Max Scherzers, Jeff Samardzijas, and David Phelpses of the world and fewer shares from the likes of Julio Urias, Kenta Maeda, or Alex Reyes than I might have in seasons past.