PHOENIX (AP) — Nolan Arenado was slugging his way through the month of May when the Arizona Diamondbacks third baseman woke up one morning with an ailment that's familiar to those who felt invincible in their
20s but have advanced to their mid-to-late 30s.
His back hurt.
Not bad. Not enough to keep him out of the lineup. But it was one of those inexplicable moments that comes with being an aging Major League Baseball player — threatening to derail a hot streak for an eight-time All-Star who just turned 35.
“There's more aches and pains,” Arenado said. “There's just a little more work in the gym, getting prepared for the game, than there used to be. That's a learning curve.
"I've always been in the gym, always did that stuff, but there's definitely more maintenance.”
Arenado got past the minor back issue and is continuing a bounce-back season in the desert, batting .256 with eight homers and 30 RBIs through Monday's games. He's among a group of the 35-and-older crowd getting solid results at the plate, joining Los Angeles Dodgers veterans Freddie Freeman and Max Muncy, along with Houston's Christian Walker.
But it's a small club that's become smaller over the past decade.
MLB hitters who are 35 or older have combined to provide just 5.6 WAR (Wins Above Replacement, per FanGraphs) through roughly the first 1/3 of the season, continuing a trend that's accelerated over the past decade.
In the early 2000s, older stars were the norm in the big leagues. It peaked in 2003 when older hitters combined for 71.3 WAR, with a group highlighted by Barry Bonds, Frank Thomas, Kenny Lofton, Luis Gonzalez and Jeff Bagwell.
So what's changed?
Let's look at some of the reasons why MLB is skewing younger this days:
Baseball's analytical era can be traced back to the work of Bill James in the 1970s and 1980s, but terms like WAR, wOBA, BABIP, and OPS+ didn't start to become widespread in the big leagues until at least the late 2000s.
Suddenly, the eye test wasn't enough for MLB general managers. Cold, hard numbers were in.
And — overwhelmingly — those numbers showed that the best years for a big league hitter usually come from their mid-20s to early 30s.
That's directly correlated to MLB teams locking up young players to long-term contracts. Arizona's Corbin Carroll, Detroit's Kevin McGonigle, Pittsburgh's Konnor Griffin, Kansas City's Bobby Witt Jr. and Seattle's Julio Rodriguez are among dozens of promising players who were signed to lucrative deals well before they reach free agency.
Spending on veterans is no longer in vogue. Walker — a three-time Gold Glove first baseman who has hit nearly 200 career homers — signed with the Astros for a relatively modest $60 million, three-year deal after the 2024 season when he was 33 years old.
“I think it has a lot to do with the ability to measure guys’ value on the field,” Walker said. “For a long time, WAR didn’t exist, wRC+ wasn’t a stat, right? So, you went off of the optics or this guy’s a good clubhouse guy or he’s got experience, he’s been to a World Series.”
Today's young stars have come of age in a game where velocity is king, but it wasn't that way when Freeman and others broke through. The average MLB fastball in 2026 is north of 94 mph, with 18 qualified pitchers averaging at least 96. When Freeman debuted 17 years ago, the league-wide average was under 92 and no qualified pitchers averaged at least 96.
Arenado said that one of the first things that becomes tougher for MLB veterans is the ability to handle really good fastballs — particularly inside. It makes for tough matchups against pitchers like Milwaukee's Jacob Misiorowski, who routinely throws 100 mph.
“I feel like just the general age of the levels and the development is trending younger and younger,” Walker said. “And there might be something to that — like your best bullets might be when you’re 27 years old.”
Dodgers manager Dave Roberts has Freeman and Muncy in his lineup on nearly a daily basis. He also played in the big leagues until he was 36 years old, retiring in 2008, giving him some personal experience on the aging process.
“The hardest part is to expect and want the same output you've always had, but not be willing to change the equation,” Roberts said.
Roberts said the process is different for every player. Some need to work out more. Some less. Others need more sleep. Diet becomes more important. The tricky part is that the habits that brought you to the big leagues might not be the same ones that will keep you there in your mid-to-late 30s.
Walker, who didn't become a starter in the big leagues until he was 28, said he's embraced getting older and enjoys analyzing his blood tests that might signal what's causing vitamin deficiencies or inflammation. The tests also show how much alcohol might affect his body or the importance of a good night's sleep.
“For myself, no real magic recipe, just chalk it up to being a late bloomer,” Walker said. “My age is older than most guys, but service time isn’t. I haven’t been in the big leagues for 20 years or anything like that. Just fortunate that I still can help the team.”
Diamondbacks manager Torey Lovullo said he believed there were two main reasons Arenado was still having success in his 14th big league season. First, he gave credit to the D-backs' hitting coaches.
But maybe most importantly, Arenado has listened to those coaches, embraced change and found new ways to have success.
“There's an adjustment to work habits and mindset once you get to that level where things aren't as easy as they used to be,” Lovullo said. “Some say ‘I’ve had my career, it's not as easy as it once was, and I want to shut it down.'”
Later he added: "It's fun to watch Nolan Arenado have all this success, but he's worked his butt off. He's working as hard as any 22 or 23 year old we have on this team."
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AP Sports Writer Kristie Rieken in Houston contributed to this story.
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AP MLB: https://apnews.com/MLB
