Mariners’ top pitching prospects off to different starts in Double-A

Arkansas Travelers games have been appointment viewing on Fridays and Saturdays for those who follow the Seattle Mariners’ prospects closely.

Those are the days top Mariners pitching prospects Kade Anderson and Ryan Sloan have been taking the mound for the organization’s Double-A affiliate. However, the young pitchers are having very different starts to their seasons.

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Anderson, the No. 3 overall pick in last year’s draft, has delivered gem after gem through the first four pro starts of his career. Sloan, a second-round pick in 2024, looks to still be finding his way, though he showed some good signs in his most recent start Saturday.

Here’s a look at how the top arms in Seattle’s farm system have fared thus far.

Kade Anderson

Anderson was viewed as the most pro-ready pitching prospect in the 2025 MLB Draft, and he’s shown why early on with the Travelers.

The 21-year-old Anderson has posted a sparkling 0.48 ERA and 0.70 WHIP while holding opponents to a .143 average over 18 2/3 innings. He’s struck out 30 batters along the way while surrendering just nine hits and four walks.

Anderson, ranked as the No. 3 prospect in the Mariners’ farm system and 20th in all of baseball by Baseball America, leads the Texas League in ERA, is second in strikeouts and third in WHIP and opponents’ batting average.

The left-hander’s promising start to the season included striking out 11 batters over five no-hit innings in his second start on April 10. In his most recent outing on Friday, he took a no-hitter into the fifth before surrendering a base knock and having his outing cut short at 4 2/3 scoreless innings by a weather suspension.

Anderson has pounded the strike zone so far as well with 69% of his pitches being strikes, including 60.3% on the first pitch of at-bats. It’s helped him post an eye-popping 44.1% strikeout rate.

Additionally, Anderson is keeping the ball on the ground when he allows contact with a 57.6% groundball rate.

The Mariners are already nearing having a crowded rotation at the big-league level. When Bryce Miller returns from his rehab assignment, which is expected to be in mid-May, they’ll have six MLB-caliber starters to choose from. Anderson is making a strong case that number will actually be seven.

Ryan Sloan

After being one of the Mariners’ standout prospects during spring training, Sloan has gotten off to a bit of a rocky start in Double-A, posting a 5.65 ERA and 1.60 WHIP in his first four starts. That has included allowing at least two runs in each outing.

The 20-year-old Sloan is still striking out batters at the same 27% clip that he had in 21 starts across Single-A and High-A last season. But he’s struggled with walks after displaying excellent command a season ago. Sloan’s 12.7% walk rate this season is nearly triple the 4.5% clip he posted in 2024.

Sloan also appears to be on the receiving end of a little bad luck so far. His 3.97 FIP and and 4.38 xFIP are well under his ERA, and opponents have a .378 BABIP against him that is almost certainly unsustainable.

Sloan’s start on Saturday showed some signs that he’s started to turn a corner. The right-hander pitched 4 2/3 innings and struck out seven batters (both seasons highs). He also allowed only one earned run, a season low.

Sloan was the highest riser in Baseball America’s recent top 100 prospects update, even surpassing Anderson in the site’s rankings as the second-ranked prospect in the Mariners’ organization and No. 19 across baseball.

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