4 prime prospects Royals fans must pay attention to in Arizona Fall League

The Arizona Fall League, the annual fall baseball festival Major League Baseball touts as a "finishing school" for the top prospects big league clubs select and spread across a half-dozen teams, launched its 2025 season earlier this week.

And right in the thick of the action are seven Kansas City Royals prospects hoping to further polish their professional résumés with good performances for the Surprise Saguaros before the AFL schedule winds up in mid-November.

Expect big things from Royals pitching prospect Dennis Colleran

Count Colleran, a right-handed collegian from Northeastern drafted in the seventh round of the 2024 amateur draft, among Kansas City prospects who didn't attract much attention this season.

And that's a bit of a shame. Working exclusively in relief, Colleran's campaign-long excellent pitching justified the swift rise he made from Single-A to Double-A ball — he opened his pro career with a 4-0, 4.06 effort at Columbia, then went 5-0 with a vastly improved 1.83 ERA at High-A Quad Cities, and closed out his rookie campaign with a scoreless inning for Double-A Northwest Arkansas, where he'll likely begin the 2026 season.

He finished 2025 with a 9-0 record, 2.85 ERA, and 1.06 WHIP. Excellent numbers to be sure, especially for a young hurler who underwent Tommy John Surgery in college. Fortunately, he's showing no lingering ill effects of the underlying issue.

Colleran threw a scoreless inning to help Surprise beat Glendale in extra innings Wednesday night.

Pitcher Logan Martin deserves close scrutiny this fall

Martin hasn't had a questionable season since Kansas City took him in the 12th round of the 2023 draft. He signed quickly, immediately reported to the Arizona Complex League where he struck out six in three scoreless appearances, then closed out his first, albeit short, campaign with a two-start 3.60 ERA at Single-A Columbia. Back with the Fireflies for the entire 2024 season, he went 4-3 with a 3.62 ERA spread across eight starts and 17 relief appearances.

The right-hander moved up to High-A Quad Cities this year and in 22 starts lowered his ERA to 3.45, won eight games and lost four, displayed decent control, and averaged less than half a homer per game.

His career numbers — 12-7, 3.49 ERA, and a .221 OBA in 51 games — suggest he may well be a starter or reliever the Royals can depend on down the road.

Martin started against Glendale Wednesday night and worked three scoreless, one-hit innings.

No. 2 Royals prospect Blake Mitchell bears close watching

Mitchell wasted no time rocketing to the top of MLB Pipeline's Kansas City prospect rankings, reaching that coveted spot little more than a month after the club made him its first pick in the 2023 amateur draft.

Jac Caglianone unsurprisingly displaced him last year, but Mitchell rose back to the top when Caglianone's big league playing time knocked him out of Pipeline prospect consideration.

Now, Mitchell finds himself behind Carter Jensen who, like Caglianone, finished the 2025 season in the majors. Mitchell didn't fall far, though — Pipeline ranks him second, and he should regain the top position when Jensen inevitably loses his prospect status early next season.

Mitchell has yet to distinguish himself statistically as the superb hitter the Royals believe he can be. He's hitting only .223 since launching his pro career shortly after the 2023 draft, but he also missed much of this season recovering from hamate surgery.

There's much to be excited about with Mitchell, though — the 18 homers he clubbed in 111 games two seasons ago prove his power potential, and owns an eye-popping three-campaign .379 OBP.

And he was 4-for-8 with two RBI and four runs scored through the Saguaros' first three games.

Look for A.J. Causey to stay in the headlines for the Royals

Causey took the minors by storm in his first professional campaign this year. Drafted by Kansas City in the fifth round of the 2024 draft, he sizzled from start to finish this season, first going 8-2 with a 1.56 ERA at High-A Quad Cities, then 3-3 with an even lower 1.56 ERA after an early July promotion to Double-A Northwest Arkansas. He had an aggregate 0.90 WHIP and didn't give up a home run in any of his 48 appearances.

Numbers like those bode well for a bright future in Kansas City's bullpen.

Causey pitched an inning in Surprise's Wednesday victory over Glendale. Although the Desert Dogs nicked him for a run and a walk, he struck out two.