Just how good have the 3 big Mariners starting pitchers been?

We look at just how dominant the top 3 starters for the Mariners have been. How does that compare against the other top pitching staffs in the AL? How far can the Mariners pitching staff take the Mariners?
Seattle Mariners v Chicago White Sox
Seattle Mariners v Chicago White Sox / Michael Reaves/GettyImages

Coming into the 2023 season it was widely known that the Mariners had one of the best rotations in all of baseball. With Luis Castillo anchoring a young and upcoming staff of George Kirby, Logan Gilbert, and guys like Bryce Miller and Bryan Woo on the doorstep. The pitching staff has held up their end of the bargain, giving the team many chances to walk away with a win. This is something that will prove critical come playoff time.

When you look at a short 3 game series, give me Castillo, Kirby, and Gilbert versus any teams top 3 any day of the week. That is the topic of today’s article. The pitching staff has been on another level, especially as of late. I want to touch on how good they have been and the odds of the Mariners winning a playoff series based solely on how good the pitching staff has been. According to FanGraphs, the Mariners have 3 of the top 20 starting pitchers, in all of baseball. Since August 5th, the Mariners have gone 15-5 and in that time Mariners starting pitching has gone 9-1 with 7.52 K/9 and 1.35 BB/9 with a miniscule 2.69 ERA.

Luis Castillo - 11-7, 3.01 ERA 164 1/3 IP, 181 K's, 1.004 WHIP, 9.9 K's/9, 2.1 BB/9

We are starting off with the Mariners ace, Luis Castillo, he has been one of the best and most dominant pitchers of the last 3 years. He was traded to the Mariners midseason 2022 and compiled 150 1/3 IP, with 167 Ks, and an improved upon, 2.7 BB/9 and elite level 10.0 K/9. Castillo has built upon that season and has really taken to the rotation as well as the city of Seattle. Castillo has been the leader of this staff on and off the field. I would trust him going up against any of the other AL playoff teams ace and feel very confident we have the advantage. He has shown us why the Mariners paid top dollar to acquire an elite-level arm.

George Kirby - 10-8, 3.28 ERA, 156 1/3 IP, 142 K's, 1.030 WHIP, 8.2 K/9, 0.8 BB/9

George Kirby was one of the Mariners top prospects and moved fairly quickly. He has shown elite level command to the tune of a .8 BB/9 this year, by far the league leader. In my opinion, he has started to challenge Luis Castillo as the “ace” of this staff, he has been that good. He would be the ace on probably every other team in baseball minus maybe 3 teams or so.

George Kirby has been relied upon to dominate teams, and give the bullpen a day off, going 6 or more innings in 9 of his last 12 starts. The Mariners are at a significant advantage if you figure that George Kirby would be going up against any other teams #2 starter. I think George Kirby must be one of, if not the best, #2 starters in all of baseball.

Logan Gilbert - 12-5, 3.66 ERA, 155 IP, 153 K's, 1.045 WHIP, 8.9 K/9, 1.6 BB/9

Isn’t it crazy we are here talking about the Mariners #3 starter? This is where the Mariners really start to separate themselves from other pitching staffs. Gilbert has been almost as good as George Kirby on paper. He has taken steps forward to improve command as well as improve upon his "stuff". Gilbert is arguably the #1 starter on 2/3 of teams across the league and the Mariners will be able to throw him in game 3 of a playoff series. He has really taken steps forward this year with his improved off-speed and an impressive splitter that has added to his above-average stuff, translating to more strikeouts for the 3rd year starting pitcher.

When you look at the playoff teams and their 1 through 3 starters in the AL it looks like the Orioles (Kyle Gibson, Kyle Bradish, Tyler Wells), Texas Rangers (Nate Eovaldi, Jon Gray, Dane Dunning), Houston Astros (Framber Valdez, Justin Verlander, Hunter Brown), Tampa Bay Rays (Zack Eflin, Tyler Glasnow, whatever healthy pitcher they have), Minnesota Twins (Sonny Gray, Pablo, Lopez, Joe Ryan).

As you look at these, I think it is pretty obvious that Castillo can go toe-to-toe with any of these teams #1 starters. As I said previously, when you put Kirby and Gilbert up against these teams #2 and #3 starters, the Mariners really start to separate themselves from these other teams, even more so when you get into the back of the rotation.

The Mariners offense has been on fire and has won them a lot of games recently. This has somewhat overshadowed just how good the starting pitching has been. Come playoff time, the Mariners pitching will be what carries them into a deep playoff run. If the Mariners can get to the playoffs, with the way the offense has been paying, I like their odds as this is when your pitching depth really starts to prove important and separate the teams. If they keep this up, there is no reason that a World Series run is a legit opportunity for this team. This has the makings of the late 90’s Atlanta Braves or the 1960’s Los Angeles Dodgers if they can all remain healthy. We need to sit back and appreciate just how great this starting rotation truly is.