Should the Royals re-sign Mike Yasztremski?

Once upon a time, professional baseball players were my age. Some still are. Some are older, even, although that number dwindles by the day. One such player is free agent outfielder Mike Yasztremski, whom the Kansas City Royals acquired from the San Francisco Giants in a midseason trade.

Yasztremski just wrapped up his age-34 campaign. I, too, will be wrapping up my age-34 season this upcoming March. My athletic talents have felt more or less consistent for most of the past decade, which I am thankful for.

But “more or less consistent” is different for me, a guy whose most grueling sports efforts are limited to a week of skiing up in the Rocky Mountains every winter. Yasztremski is playing at the highest level of professional baseball. I won’t notice if my turns are 2% less efficient on the slopes compared to my 29th season. Yaz will absolutely notice if his swing is 2% slower, because the numbers will bear that out.

Next year, Yaz will be in his age-35 season. While young overall, that’s a little long in the tooth for an MLB player, especially for a hitter. And the reason for that is pretty clear: players that, uh, old have limited upside.

Last year, there were only 17 hitters in their age-35 season that managed to accrue 150 or more plate appearances. If you take out the clear outliers—surefire future Hall of Famers Freddie Freeman, Giancarlo Stanton, Jose Altuve, and Paul Goldschmidt—you get a group of a dozen batters whose median Wins Above Replacement is 0.2.

That’s not to say that Yasztremski is doomed to be terrible next year. The best predictor of future performance is the most recent data set of past performance, and Yaz was very good in 2025. He walked nearly 13% of the time and posted an above average isolated power of .170, all while playing solid defense in the corner outfield.

Kansas City has been linked to Yaz this offseason, which makes sense. The same factors that drove the initial trade are still in play, which is simply that the Royals don’t have any good outfielders and lack hitting depth across the diamond. They need an outfielder. Yaz is a better outfielder than anybody else currently on the 40-man roster. He’s unlikely to need more than a one-year deal. It all lines up.

However, there is the sticky situation with Yaz’s age. Players in their mid-30s have a frustrating propensity for falling off a performance cliff. Sometimes it’s when they’re 33. Sometimes when they’re 35. Sometimes when they’re 37. The aforementioned Goldschmidt was one of the best hitters in baseball for a dozen years, and last year in his age-36 season he suddenly dropped to league average production, which he was unable to improve on this year.

Yaz has shown some signs that he may be approaching said cliff. His ISO sharply dropped from last year, even if it remains pretty good. And while Yaz has never been good against left-handed pitchers, his triple slash against lefties this year was a flatly unplayable .138/.204/.223.

Yastrzemski is ultimately a platoon bat at this point in his career. That’s fine, and he’d be a useful guy for Kansas City next year. But if the Royals sign him with an eye that he’d be one of their full-time starting corner outfielders, that would be a mistake. Yaz is plenty athletic, and I’m sure he would leave me in the dust if we were to race down a steep black diamond run.

Unfortunately for him, his competition is not just fellow 35-year-olds, but some of the most physically gifted 20-somethings on the planet. He’s still worthy of a contract, maybe even with Kansas City. But time is what it is, and the Royals should act accordingly.