The Royals might have their closer of the future at Double-A right now

Barring a ghastly and improbable September meltdown, this season will end as one of the best, if not the best, of Kansas City Royals closer Carlos Estévez's nine-year career. Through Monday, his major league-leading 38 saves exceed his previous best by seven, his 53 games finished paced big league relievers, he was holding opponents under the Mendoza Line at .196 and, had the season ended after the Royals' crushing 10-2 Monday loss to Cleveland, his 2.49 ERA would be second only to the career-low 2.45 he posted last year.

But because the demand for them is always high, top closers like Estévez walk a fine line between long-term single-club mainstays and premium value trade targets. So, even with another season left on the free agent deal he signed last winter, and the club option Kansas City holds for 2027, Estévez isn't guaranteed to last long as a Royal. If another club offers general manager J.J. Picollo more than he can refuse, this season's back-of-the-bullpen hero could be gone.

And if that happens, Lucas Erceg, the fine reliever who quickly became KC's closer after arriving via a midsummer trade in 2024 but found himself displaced by Estévez when this campaign began, would be the favorite for the role.

Don't be surprised, though, if the Royals have someone else in mind should they choose to move on from Estévez in the next couple of seasons. And that someone could be A.J. Causey, who'll complete his first professional season sometime this month.

A.J. Causey might be the closer of the future for the Royals

Although he didn't pitch in a professional game last year after the Royals took him in the fifth round of the 2024 amateur draft, Causey is turning too many heads and pitching too well not to have already landed on Kansas City's bullpen radar. Assigned to High-A Quad Cities to begin this season, the potential-packed right-hander struck out four and didn't walk a batter in his April 5 pro debut, and has rarely missed a beat since.

Only three times in 46 relief appearances — 27 with the River Bandits and 16 for Northwest Arkansas after his July 8 promotion to Double-A — has Causey been charged with more than one run (he gave up two each time). He's saved eight games and permitted only two of the 17 runners he's inherited to score.

But those aren't Causey's only impressive numbers. Entering Tuesday, he's fanned 73 and walked only 18 in 72 innings, owns a 0.89 WHIP, and is limiting opponents to a .183 average. He earned his way to Double-A by going 8-2 with a 1.56 ERA at Quad Cities, and is 3-1 with a 1.71 ERA at Northwest Arkansas. Between the two minor league clubs, his ERA is 1.63 and he's 11-4.

The Naturals' season ends September 14, so it will be interesting to see if the Royals bump Causey up to Triple-A Omaha — since the Storm Chasers don't wrap up the 2025 campaign until September 21, he could get a taste of the minors' top level before next season when he's a sure bet to begin the year with Omaha.

No matter what he does the rest of this season, whether Causey is in fact in the running to become Kansas City's closer of the future remains a good question. Like many sidearmers, he doesn't have an overpowering fastball, but his overwhelmingly good numbers suggest he has what it takes to guard late-inning leads.

Time will tell, but it looks like the Royals are grooming a legitimate closer candidate.