Why Bryan Woo could be the pitcher who determines the Mariners success in 2024

Bryan Woo isn't at the level of the Mariners top 3 SP (yet), but his 2023 numbers portend dominance for 2024 that could push the Mariners to an AL West title
Los Angeles Angels v Seattle Mariners
Los Angeles Angels v Seattle Mariners / Steph Chambers/GettyImages

Let's focus solely on Bryan Woo today. No mention of anyone else in the Mariners staff, not even in their rotation. Solely Woo, who is looking to improve upon a promising rookie season in which he provided plenty of highlights. There are a handful of questions to look into for his upcoming season, and I think they are fair to ask and wonder about.

Let's start off with innings. That's the biggest one, as a full workload for a pitcher is tough when you haven't done it before. Take a look at Woo's career, all the way back to his first year of college and look at his totals.




























That's not a lot of innings in his past. From 2018-2022, a period of five years, Woo threw just 186.2 innings. A full workload in 2024 (32*5.5 innings) would be 176 innings on its own. Is it safe and reasonable to expect that jump? Logan Gilbert and George Kirby went through something similar, and I think getting Woo to ~130 was a good stepping stone. He's had the full offseason with the Mariners, and knows his expectations instead of moving around during the year.

Bryan Woo could get the Mariners to the AL West Title in 2024

So, we are good on innings. Let's take a look at some of the deeper numbers. The one's that stand out are how hard hit he is... well, lack of, that is. The league average exit velo is 88.5 mph, and Woo is well below that at 86.9 mph. It pairs with a low hard-hit rate as well (balls at 95+mph), as he is just 33.9%, WAY below the league average of 39.5%. Not getting hit a ton is a good indicator of success, and explains a bit his lower than average BABIP (softer hits are easier to get to).

It looks even better when you see that those two stats were in the 82nd and 83rd percentile last season, both nice red-hot numbers.

The fact that his breaking ball value is in the blue might actually be a good thing as well. What has the Mariners staff excelled at in recent years with their pitchers? Sliders. What did Woo struggle with last season? The slider. If they can get him up to league average or better, that's a big step for him. HIs 4-seamer and sinker both had positive run values. Up his slider to that, and it becomes a strong 3-pitch repertoire that is much harder to hit.

I mentioned that his BABIP was lower than the league average last year, but there is an argument to be made that it could've been even lower. His xBA was a bit higher than BA on his sinker (.234 to .213) but was lower on his fastball (.192 to .207), his cutter (.238 to .261), and his slider (.208 to .257). That's still a fair amount of balls that ended up as hits that shouldn't have been. Oh, and his xSLG was lower on every single pitch than the actual SLG, another good sign.

There is a real argument here that Woo was a bit unlucky last year. It doesn't seem like a big IF statement to say that, if Woo repeats his 2023 work on the mound, that he is going to have a great 2024. Not Cy Young worthy, but good enough to surpass Miller for the #4 spot, and start some quiet conversations about pushing towards those top guys in the rotation.

Of course, it's early in his career, and he could easily regress with his command, or go through rough patches, but the talent and numbers are there for success. Woo could be the won who solidifies the Mariners at the top of the AL West.