The Growth of Anthony Rendon

It’s been a big sophomore season for Anthony Rendon. After a passable, but somewhat underwhelming, rookie year, Rendon has emerged as one of the Washington Nationals best players. By WAR, Rendon has been the Nats best position players this season. But if you’re skeptical of defensive numbers, he’s rated as the third best hitter on the team this season, behind Jayson Werth and Adam LaRoche. Rendon’s improvement shouldn’t come as a major surprise. Yes, Rendon’s improvement has been large, but he was a top draft pick and came with a strong pedigree. With the season entering its final month, it’s time to wonder whether there’s more room for improvement in Rendon’s bat.

Since we’re only concerned about Rendon’s offensive output in fantasy leagues, we can push his defensive value aside here. In order to figure out how common his offensive surge was this season, and whether it typically leads to a better performance, we need to find some comps for Rendon. We can do this by finding similar wOBAs based on his age and position. Since Rendon can play both second and third, we’ll take players from each position for our sample.

When looking at 23-year-old infielders who have posted a wOBA within 10 points of Rendon, we come up with 36 players. For the purpose of this exercise, let’s limit the list to the players who actually managed to improve their wOBA during their age-24 seasons.

We’re left with a list of 14 players.

Name	wOBA age-23	wOBA age-24	Dif
Mike Schmidt	0.322	0.417	0.095
Fernando Tatis	0.326	0.411	0.085
Pablo Sandoval	0.316	0.383	0.067
Carney Lansford	0.315	0.376	0.061
Matt Williams	0.307	0.352	0.045
Rick Schu	0.309	0.345	0.036
Anthony Rendon	0.318	0.348	0.030
Alex Gordon	0.316	0.343	0.027
Steve Braun	0.32	0.331	0.011
Rennie Stennett	0.315	0.323	0.008
Gary Gaetti	0.315	0.322	0.007
Gregg Jefferies	0.323	0.328	0.005
Brett Lawrie	0.314	0.319	0.005
Aaron Hill	0.322	0.323	0.001

There are three players on that list who experienced similar breakouts at age-24. Those players are Matt Williams, Rick Schu and Alex Gordon. Williams’ improvement may have been too high, but I’m cheating and including him since he currently manages Rendon. On top of that, Rick Schu is the Nationals current hitting coach, so there are plenty of coincidences here. Gordon is actually a pretty interesting comp. He started to show plenty of promise during his sophomore season only to struggle again for the next two seasons. He eventually blossomed into an All-Star player, albeit in the outfield.

Given that we can’t just look at three players to determine how Rendon will perform next season, let’s look at how all the players below Williams performed at age-25. That’s only an eight-man sample once you remove Brett Lawrie, so take that into account here.

Name	wOBA age-24	wOBA age-25	Dif
Gregg Jefferies	0.328	0.395	0.067
Steve Braun	0.331	0.382	0.051
Matt Williams	0.352	0.352	0.000
Aaron Hill	0.323	0.343	0.020
Alex Gordon	0.343	0.315	-0.028
Rick Schu	0.345	0.312	-0.033
Gary Gaetti	0.322	0.302	-0.020
Rennie Stennett	0.323	0.282	-0.041

The results are, not surprisingly, mixed. Jefferies and Braun had huge breakouts, Williams performed at a high level again and Hill showed a nice improvement. The other four players saw pretty steep drops in their numbers. Both Gordon and Gaetti represent the base case of the failures, as both went on to emerge as strong offensive players in the majors. Schu never reached the heights of his age-24 season, and Stennett only had one year where he reached his former glory.

It’s tough to be too optimistic about an eight-man sample, but it’s promising that six of these players worked out in the long run. While we shouldn’t expect Rendon to suddenly post a .380 wOBA next season, more of the same doesn’t seem like a long-shot. Rendon’s made a big jump during his sophomore season. More of the same can be expected moving forward.