I like to think that we are all aware that we get to watch baseball in an era where the best position players are younger than in past eras. The five best players in 2019 according to Fangraphs WAR are as follows:
Unsurprisingly, they are all 27 or younger. If you’ve watched baseball games or listen on the radio, you’ve probably heard an announcer or a former player say, “these guys that are getting called up are more polished than ever.” The trend is so obvious, you don’t even need statistics to believe what your eyes are already telling you. Young players in MLB are better than ever.
Since so many of the league’s best players are so young, I was interested to see if there was an enhanced performance from VERY young players, in particular I turned my interest to the rookies. I asked the question: Are rookies in 2019 outperforming rookies of years past? Will they match the trend of younger players that we are already aware of?
Going into this, I swear I’ve seen more rookie home runs this season than any season in my lifetime. I know that there are more home runs in general, but It just feels true.
A note up front here: This only includes position players and not pitchers.
I started by just looking at total WAR generated by rookies from every year between 1980 and 2019 (I’ve generated a projected WAR for 2019 here so it matches the other years).
The first thing that you see in this graph is that total WAR from rookies has steadily been rising over the past two decades. Bulk WAR tells us that we are seeing an increased output from rookies as a total crop, but this can be skewed by the number of rookies that each crop had. In order to control for that, I also looked at the number of rookies (Min 150 PA) in each season, and generated a statistic I am calling WAR/rookie. Which takes the total WAR from rookies on the season, and divides it by the number of rookies in that season. That graph looks like this.
You can see that similar to the first graph, there is a steady increase since about 1995, and we see a sharp spike up this season in 2019. This generally confirmed everything that I expected to see in terms of gross production in Wins Above Replacement. So what if we drill down to look at the hitting from the rookies? I figured wRC+ was a good statistic here since it is normalized for the run environment in each year, and would control nicely for the steroid era in the 90’s and the juiced ball era of today.
Now this is something! Not only are 2019’s rookies outperforming every rookie class since 1980 at the plate, but this is the first year in this 40 year period where rookies have been above average (100 is average in wRC+) in hitting relative to the rest of the league. I don’t think I can stress that enough. How many jobs do you go to work on your first day, and know that you are better than the average employee? Even within sports, it is unprecedented that rookies enter their respective league and produce above average numbers as a group. These rookies are entering the most competitive baseball environment in the world, and it’s never been more exciting to watch these kids play.