Is it possible to predict how well soccer players will age?

One of the secrets to soccer, a multi-million-dollar question with a hundred-million-dollar answer, is understanding how players age. Imagine if, say, you could tell the difference between Eden Hazard and Karim Benzema?

At 27, Hazard was arguably the best player in the Premier League -- one of the only players in the world who was an elite outlet, ball-mover and goal-creator. In NFL terms, he was a running back, wide receiver and quarterback all at once. In his age-27 season, Hazard scored 16 goals and assisted 15 more in domestic play. In the four seasons since, he scored 11 and helped on four -- total. Almost overnight, Hazard transitioned from one of the 10 best players in the world to total irrelevance at the top level.

At 29, Benzema looked finished. He scored five goals and assisted 10 more -- respectable numbers if you're an average player, but disappointing if you're Real Madrid's starting center forward. The prior year wasn't much better, either: 11 goals and five assists. Then, he turned 30 and ... averaged 23 goals and nine assists over the next four seasons. Benzema won the Ballon d'Or, in a landslide vote, at 34. He peaked after his peak was supposed to end.

These players, of course, eventually played for the same team. Hazard joined Real Madrid after that lights-out age-27 season. And so the club has experienced first-hand the frustrating vagaries of how players improve and decline and age.

On the one hand, signing Hazard for €100 million was a lesson in why you don't invest such large transfer fees in older players: they usually get worse. And yet from age 30 on, Benzema's performance was worth so much more than €100m. Had Madrid given up on the Frenchman back when he entered his third decade, they probably would have two fewer LaLiga titles and just 13 Champions League trophies.

The lesson from these two stories might seem like it should just be that most players don't age gracefully, but Real Madrid also just happened to hang onto one of the few who do. It's all random; don't chase the outliers.

However, ahead of Real Madrid's derby clash with Atletico on Sunday (stream LIVE on ESPN+, 3 p.m. ET) new research suggests that there might actually be a pattern to all of this -- a reason why certain players last longer at the top than others.