The Mariners are calling up Kade Anderson to make his MLB debut on Saturday against the Cubs, ESPN’s Jeff Passan reports. Bryan Woo was scheduled to start that game and will presumably be rescheduled for Sunday. Seattle will need to make an active roster move involving a pitcher. They will also need to open up a spot on the 40-man roster, but they can do so by transferring Matt Brash to the 60-day injured list without affecting their schedule. Brash has already missed more than 60 days with a lat strain. President of baseball operations Jerry Dipoto teased a promotion for Anderson earlier this month, saying they would only do it when a rotation opportunity arose. “We’re not going to put Kade in the bullpen. He’s the best starting pitcher in the minor leagues,” Dipoto said in early August (link via Daniel Kramer of MLB.com). He continued to call Anderson “the next starter” behind his front five after the M’s traded Luis Castillo to the White Sox. This likely indicates the Mariners will adopt another six-man rotation. They are not dealing with any injuries to their starting five. George Kirby and Bryce Miller have been beaten this month, so the M’s could send one of them to the bullpen if they wanted to stay on a five-man schedule, but that would be a surprise given their respective track records. Most evaluators consider Anderson the best pitching prospect in the game. Keith Law of The Athletic ranked him the No. 1 overall prospect in his most recent update shortly before the trade deadline. Seattle nabbed the 6’2″ lefty with the third overall pick in the 2025 draft. He did not pitch professionally last year after throwing 119 innings in his second season at LSU. The M’s assigned him to Double-A Arkansas this year and, as Dipoto mentioned, he has completely dominated the level. In 18 starts, Anderson has a 1.06 ERA with a 41% strikeout rate. He has the best strikeout and ERA rate among all minor league pitchers with at least 80 innings. He’s coming off four straight scoreless outings while holding opposing hitters to a ridiculous .147/.183/.216 line in 333 plate appearances. Double-A hitters clearly can’t touch Anderson. Seattle is content to outplay him in the hitter-friendly Pacific Coast League and test his talents against MLB competition. Anderson has advanced command of a four-pitch combination (fastball, changeup, curveball, slider) that qualify as above-average or above offerings. He is considered a possible starter at the top of the rotation. Seattle has been among the best teams in the game at developing college pitchers. Their entire current rotation came via the draft and development route. Miller and Woo were mid-round picks, while Anderson joins Kirby, Logan Gilbert and Emerson Hancock as former first-round picks in the rotation. They’re one of the strongest groups in the majors on paper, but they’ve been adding to the underperforming offense and bullpen lately. The Mariners’ starters entered Thursday’s game with a 4.46 ERA since the All-Star break, the eighth-worst mark in the majors. Kirby was shelled for six runs in 3 1/3 innings in today’s loss at Milwaukee, which won’t do that mark any favors. It also dropped Seattle eight games below .500 to 60-68, a surprisingly poor record for a team that was one game away from the franchise’s first trip to the World Series a year ago. That at least raised questions about whether the M’s would abandon their plans to call up Anderson this season. He would not have been eligible for the Rule 5 draft. The Mariners could have opted to keep Anderson off the 40-man roster and preserve his eligibility to play in the minor leagues in 2027 if the lockout results in canceled MLB games. They have chosen not to go down that path, hoping that Anderson can help them turn their fortunes around this year. The overall mediocrity of the American League is the only reason the Mariners aren’t completely buried. They are in third place in the American League West, 4.5 games behind the Astros and 2.5 behind the Rangers (pending those teams’ games on Thursday). They are three games behind a 63-65 Twins team that now has the final wild card spot, although there are five teams between them and Minnesota. Seattle waited long enough into the season to preserve Anderson’s rookie eligibility through 2027. He would be eligible for the Prospect Promotion Incentive next year. If he breaks camp (or is called up in mid-April), he could land them a future draft pick, either by winning the ’27 Rookie of the Year award or finishing in the top three in Cy Young voting within his first three full seasons. Anderson will not be eligible for arbitration until the 2029-30 offseason and will be under club control through the 2032 season if the service structure does not change in the next collective bargaining agreement. Image courtesy of Steven Branscombe, Imagn Images.
