How Does Age Impact Projection Accuracy?

Can You Teach an Old Dog New Tricks (Wins)?

“There’s always next year!” That’s what baseball fans have become accustomed to saying in the fall. This time of year? It’s Casey at the Bat’s “hope springs eternal”, or “DUDE! You should see him. This guy’s in the best shape of his life”… or even the new, “he looks great on insert social media platform here”.

We as baseball fans love tradition. We love a narrative. Each spring, throughout my entire life, the narrative this spoiled Yankee fan has bought into is that the Yankees are going to be good this year.

Earlier this week, Fangraphs published their playoff odds for the 2024 season. Who did they project to win the AL East? Not the Red Sox who have barely shown signs of life this offseason. Not the “paper tiger” Blue Jays whose Bo Bichette may steal as many major league bags as me this season as his sprint speed descends Statcast leaderboards faster than Terrance Gore stacks up steals and World Series rings. It’s not the analytical gods down in Tampa. Nor is it even the defending AL East Champs who can brag about having last year’s Rookie of the Year (ROY) winner, this year’s ROY favorite, and just added a top three pitcher in the sport in Corbin Burnes to their roster. Nope. You guessed it. It’s the New York Yankees. And you wonder why everyone hates us.

Over the past few years, part of the narrative on why the Yankees continue to underperform projections like these from Fangraphs is because they have an aging roster that is prone to injuries. Last year, for example, Aaron Judge missed time when his foot collided with the concrete wall in Dodger Stadium. Carlos Rodon never got right after an offseason back injury. Anthony Rizzo attempted to play through a concussion suffered during an on-field collision with Fernando Tatis Jr… Nestor Cortes missed time… Jose Trevino missed time… Luis Severino missed time… DJ LeMahieu missed time… Giancarlo Stanton most certainly missed time… even the Martian, the Wunderkind, Jasson Dominguez suffered a season ending injury in 2023 when he tore his UCL and required Tommy John surgery.

But that’s all noise. Let’s dive into the premise – the Yankees roster underperforms because it is aging AND is prone to injuries. I’m not a doctor, have never received an offer to play one on TV, and thus am not a good authority to what makes someone prone to injuries in the future. But the other half of that statement we can dive into. Can we prove that age makes a roster more likely to underperform Fangraphs win projections?

To take a look, I pulled team wins from 2020 to present (queue the small sample size song by Ted Berg) and compared them with each team’s Fangraphs projected wins by season. I ran the discrepancy between these numbers against the average age for each team’s roster as listed on Baseball Reference. Please note an assumption here – before the new CBA in 2022, teams could choose how they built their roster, with varied numbers of pitchers and hitters. For 2020 – 2022, I assumed thirteen hitters and thirteen pitchers.

Visualized above, the regression analysis returned an r^2 value of 0.0003147. For those of you who don’t remember your high school or college Statistics class, a low r^2 value means that one variable does not predict the other. In baseball terms, an older team does not always lead to under/over performance.

Two real world baseball examples that support the analysis:

- The fourth oldest team last year in 2023, the Los Angeles Dodgers at an average age of 29.5 years old, was also the fourth largest out-performer, out-performing projections by 11.7 wins.

- On the other side of the coin, the oldest team in 2023, the New York Mets at an average age of 30.4 years old, was the fifth largest under-performer, underperforming by 14.6 wins.

All in all, this small sample-size analysis shows that an old roster alone does not correlate to winning or losing more games. The Yankees simply find other ways to underperform.

WCM