A version of this story originally ran in December 2022.

If there’s one secret baseball players haven’t cracked yet, it’s this: Don’t get old. While it’s never one-size-fits-all, the decline that comes with age has been studied endlessly, from hitting performance to fastball velocity to exit velocity, and it’s in part that knowledge that’s fueled the surge of youth in today’s game. That goes for running speed, too, which we knew from the day Statcast launched the sprint speed metric years ago. Get older, get slower.

Trea Turner is getting older, too, as we all do; he’ll be 30 in June. But unlike most everyone else, he’s not getting slower, not yet. After parts of eight seasons in the Majors, Turner is exactly where he was when he broke in back in 2015: Faster than 99 percent of the rest of baseball. Since his elite speed was a major reason why the Phillies committed to an 11-year deal with him this offseason, this is now more crucial for him than ever. The contract won't run out until after Turner's age-40 season.

So: What does this all mean for him?

1) Turner hasn’t slowed a bit.

Obviously, and we must begin here, because Turner has had elite speed since the day he arrived, really. You already know this, so we don’t need to spend a great deal of time to convince you of it, but what he’s done is so impressive that it’s worth being clear on. There’s eight years of sprint speed data from Statcast, and Turner has been one of the seven fastest players in baseball all eight times. He was fast eight years ago. He’s fast now.

Turner’s speed rankings, 2015-2022

• 2015: 2nd
• 2016: 3rd (tied)
• 2017: 5th
• 2018: 7th (tied)
• 2019: 2nd
• 2020: 4th 
• 2021: 1st (tied)
• 2022: 5th

It’s that consistency that stands out here. For example, Minnesota’s Byron Buxton was as fast in 2015, and has lost only a little of that speed along the way, but he’s been hurt so frequently that he’s taken just 57% of the plate appearances Turner has.

Many of the other top speedsters from the early years here – Eric Young Jr., Adalberto Mondesi, Delino DeShields, for example – have either left the sport or are hanging on as bit players. Yet Turner endures.

A better way to explain it, perhaps, is that since 2015, Turner has hit the elite 30 ft/sec threshold 724 times, where as second place has done so just 448 times. It’s the speed, sure. But it’s consistent speed, and the availability to put it to use that stands out here.

It's that consistent ability to show elite speed that runs into direct conflict with the fact that ...

2) The aging trend hasn't changed.

... Turner is human, and humans get slower as they get older.

We now have those eight years of sprint speed data, so we should be able to find some trends, and then see by how much Turner is bucking them. So let’s start at the start: Do players still get slower as they age, now that we’re nearly a decade into this? Well, yeah. By a lot. It's not at all difficult to see. You could ski down this slope.

We're talking four feet per second from the high end here to the low end, and if that doesn't sound like much, realize that the average home-to-first run takes about 4.4 seconds, and all of a sudden this adds up to pretty major differences.

The 20-year-olds, at least those who played enough to qualify for a seasonal leaderboard, averaged 28.5 ft/sec, well above the Major League average of 27, and by far the fastest here. (We’ll admit, there is some bias here in the sense that only those 20-year-olds good enough to qualify are accounted for here, and because it’s pretty rare for a catcher to be up that early.) That select group includes speedsters such as Fernando Tatis Jr. (29.3 ft/sec in 2020), but also slower runners such as Vladimir Guerrero Jr. (26.3 ft/sec in 2019).

Then it declines, steadily, until around 28 years old, when it’s more like league average, slowly declining until around 37, when it falls off a cliff, leaving mostly DH types or backup catchers.

To put some names to the idea, let's cherry-pick a few examples of players who were A) similar to Turner’s age in 2016, B) had above-average speed to start with, and C) are still active today. Look at what happened, turning the raw sprint speed numbers into percentile ranks, with 100 being “best in baseball.” Our group includes Tim Anderson, Kris Bryant, Alex Bregman, Carlos Correa, Mookie Betts and Marcell Ozuna.

Turner has remained elite, but what happened to the rest? Age, to some extent, but also injuries. Anderson has had a variety of groin, hamstring, and ankle troubles. Bryant suffered back and foot problems in 2022, though he’d begun to slow before that. Bregman has gone from excellent speed to poor, perhaps in part to quad and hamstring issues. On and on it goes: Correa has had back trouble, Betts hip problems, and Ozuna has declined from a playable center fielder to a strictly DH role, though his injuries were mostly to his arms and fingers.

Turner did once break his wrist when he was hit by a pitch, and a finger in 2019 on a bunt attempt, but his only lower body injury was a minor hamstring pull way back in the first month of 2017. He's largely avoided the kind of speed-sapping injuries many of his peers have suffered.

Of course, there are examples to the contrary, too, since we just chose a few big names to illustrate the kind of things that tend to happen over time. In the other direction, Mike Trout, Marcus Semien, and George Springer are among those who are still about as fast in 2022 as they were in 2016. Again: It’s not one-size-fits-all. The overall trend, though, is difficult to refute. Father Time always wins, eventually.

3) What happened as comparable players began to age?

So Turner hasn’t yet started to slow, that’s clear. But he will at some point, surely, and those trends that we spotlighted above apply to the Major Leagues as a whole, not someone who starts from such lofty heights as Turner had. What about just those players, the true speedsters? After all, the non-catchers in our speed list have, as a group, declined by about 0.7% per season from age 30 to age 35. If Turner did the same, then at age 35, he’d have a 28.5 ft/sec sprint speed, which would be 82nd percentile this year – or basically Trevor Story. If not elite, that would still be excellent.

We’re looking at over 4,300 qualified seasons, which is both “quite a bit” and “not really enough,” since obviously we can’t tell you anything about the careers of Rickey Henderson or Juan Pierre or even the earlier parts of the careers of Jose Altuve or Andrew McCutchen.

But that doesn’t leave us without options. Let’s try to look at what we’ve got in two different ways.

A) What happened to other recent fast players at Turner’s age?

For example: Anthony Rizzo has slowed down, but a soon-to-be 33-year-old first baseman who was never that fast in the first place isn’t exactly a good comparable here. We need speedsters.

In the first five years (2015-19) of speed tracking, we looked for players who averaged 29/ft sec or above in their age-29 season, as Turner just did. (While 29 ft/sec is not 30, it’s still outstanding.)

We found 15. A handful of those players didn’t have much career left, due to issues of injury or performance, so obviously, there’s a selection bias here. Seven of them, however, were still active in 2022, playing from ages 32 to 36. Was the speed still there?

The answer: A resounding yes, or at least enough of it. In 2022, here’s how those seven runners performed.

• 90th percentile or better: Kevin Kiermaier, Jon Berti, Andrew McCutchen
• 80th percentile or better: Whit Merrifield, Phil Gosselin
• 70th percentile or better: Dee Strange-Gordon, Lorenzo Cain

It doesn’t mean they retained all of their speed, especially the latter two, who each have shown considerable speed declines from their once-elite glory days. (Cain is now likely retired.) But if no longer elite, then at least no one fell even to average speed, much less below-average. That's a good sign for Turner.

B) What about players aging into their late 30s?

Turner’s new deal will take him well beyond his mid-30s, and not all of the players we just talked about have made it that far yet. Do we have evidence of anyone at that age or older retaining elite speed, even if all the data we have to go on is the end of their career?

It is, for the most part, grim, full of examples like Alex Rodriguez going from stealing 46 bases as a 22-year-old shortstop to one of the slowest players in the game as a 40-year-old designated hitter.

But there are good outcomes, too. We have a few hundred examples of speed data from age 35 or beyond, and these five players – so far, as McCutchen is likely to join this group next year – have had multiple seasons of above-average speed (28 ft/sec) from that point on.

• Rajai Davis (3), Brett Gardner (3), Hunter Pence (2), Lorenzo Cain (2), Coco Crisp (2).

If we lower the threshold to just average speed (27 ft/sec), then 11 players have done it.

• Ichiro Suzuki (4), Chase Utley (4), Davis (3), Gardner (3), Pence (3), Yuli Gurriel (3), Cain (2), Crisp (2), Mike Aviles (2), Jarrod Dyson (2), Ben Zobrist (2)

Again, if not necessarily elite speed at that age, then good-enough speed is still clearly within reach. (Davis, for his part, did retain elite speed into his age-38 season.) It’s possible, is the point.

Turner won’t be this fast forever, because no one can be. But barring major injury, which he’s managed to avoid to this point, there’s little worry about his speed showing worrisome decline over the next several years. Given the lofty heights he’s starting from, even a standard decline would still leave him being quite fast in his mid-30s, and that’s beyond any reasonable expectation the Phillies might have. Speed might not age well, but speed doesn’t usually start this elite, either.