Adrian Beltre: Where’s the Decline?

Adrian Beltre turned 33 before this season. No matter if you look at his plate discipline or power components, the aging curves say that he’s post-peak and we should see some decline. Not every player follows the curves the same, but look at Beltre’s recent years, and it just looks like he’s getting better. Impossible.

Of course, his home park is a major confounding factor when you’re looking at results. He suffered through SafeCo for all those years, and then was finally freed-slash-loosed-upon-the-league. According to our own Guts! page, SafeCo depressed all home runs by 4%, but all offense by 6%. Texas entices home runs by 9% and offense by 6%. That’ll mask a decline.

Can we find one anyway?

Not in his isolated slugging percentage. His last two years in Texas have produced two of his three best ISOs. Or his batting average (two of four best). Not in any of his more superficial stats, like RBI, or runs, or any of that. Well, stolen bases, yes, but you don’t own him for ten stolen bases, and his power surge has made up for any loss of wheels.

We’ve got a 33-year-old that was just a top-five third-baseman for the second year in a row, after languishing along with .270 batting averages and 20+ home runs for the meat of his career. Nothing’s on the way down?

Look at those power aging curves, and you’ll notice that ground ball rate is supposed to start increasing quickly as a player ages. Now look at Adrian Beltre’s ground-ball rates:

Certainly not getting worse, his ground ball and fly ball rates have actually gotten more power-friendly as he’s aged. Two of his most power-friendly three seasons by ground-ball-per-fly-ball rate have come in the last two years. It might just be that he saw the value of a fly ball in his new stadium and started putting more loft on the ball, but it doesn’t look like time has begun robbing him of his ability to drive the ball in the air yet.

And it’s probably by this more power-conscious approach that Beltre has managed to stave off some aging. Because even if you use a park- and league-adjusted stat like wRC+, Beltre’s had three of his four best season in his last three seasons. If you do look at wRC+, though, the gap narrows. He had plenty of season in Seattle that were under-the-radar good. Three out of his five seasons there were actually above average overall, even if they didn’t look great.

If we drill down as far as we can go, we can see the slightest whiff of decline. Look at his batted ball distance on a graph, and it seems steady:

But if you focus on his Boston and Texas years, even his more powerful approach might be eroding by a fraction. In 2010, his fly balls and home runs went 294.75 feet on average. In 2011, that number dropped to 290.85 feet. This season, he hit home runs and fly balls 287.6 feet on average. Those seven feet dropped him from the top forty in batted ball distance to 67th in the league this past season (> 80 fly balls + home runs), so even though it’s a seemingly small number, it has dropped him down the power boards. You can take a look at those batted ball distance leaderboards thanks to Jeff Zimmerman and Baseballheatmaps.

We can leave the predicting for later, but if his home-run-per-fly-ball rate regresses to his career levels (13.8% career, over 16% the last two years), and his batted ball distance continues to erode, you’ll see a player whose home run power will slip. And his batting average too. And then maybe one of those injuries that kept him from accruing 600+ plate appearances in 2009 and 2011 will come back.

Adrian Beltre will probably still be a good third baseman next year. That isn’t to say that his age-related decline hasn’t yet begun.