Mariners monitor workload for rookie starters

June 30th, 2023

This story was excerpted from Daniel Kramer’s Mariners Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

SEATTLE -- Marco Gonzales received positive news from Dr. Neal ElAttrache when visiting the renowned orthopedist this week in Los Angeles. But the latest prognosis of his left flexor strain revealed more nerve damage than initially diagnosed, and he was instructed to refrain from throwing for at least two weeks.

The Mariners’ left-hander is still optimistic about his rehab, but the pivot will also further require him to regain arm strength once he’s cleared to resume throwing, putting the timeline on his return deeper into summer.

Seattle’s rotation has stayed plenty afloat with his fill-in, rookie , who continues to impress, but a healthy Gonzales can do something the 22-year-old righty can't yet: eat innings.

The Mariners have made it no secret that Woo, who surpassed his 2022 innings total (56) in his recent start against Washington on Tuesday, will be monitored far more closely as the club presses into summer, much like Logan Gilbert and George Kirby each of the past two seasons.

The good news is that the All-Star break looms, and with it, baked in off-days and the chance to re-slot the rotation entirely entering the second half. It’s highly likely that Woo will be optioned to the Minors at some point for abbreviated outings to curb his workload, too, much like Kirby last summer.

“We've talked about different options and where we'd go,” Mariners manager Scott Servais said. “You start looking at how many starts he's got leading into the break and then how you want to line it up coming out of the break, things like that. So those discussions are going on right now.”

However, Servais added that Woo will make at least one more start before the break, next week in San Francisco, the venue where he grew up attending games as a Bay Area native.

“He might choke me if we don’t,” Servais said, laughing.

It’s possible that the Mariners re-slot their rotation following Thursday’s off-day so Woo would only make the one rather than a second in Houston the following weekend.

But it’s hard to envision, at this rate, seeing Woo pitch his way deep into the fall given the risk of burdening his arm with more than it's ever been accustomed. The same goes for fellow rookie , though Miller reached 133 2/3 innings last year and is at 75 1/3 this year.

“We’re also going to have to be creative as we go with off-days and understanding there’s a certain limit to what you can do there,” Mariners GM Justin Hollander said. “There may be a point where we have to shut one of them down because they just have reached a point where it’s too big of a stretch on their innings.”

The Mariners don’t operate with a specific number in mind, at least publicly, on how they track workloads. It’s far more detailed based on assessments from their high-performance staff and more.

“It’s incumbent upon them to be as efficient as possible in the innings they have so we can get them through five- and six-inning outings at a reasonable pitch count," Hollander said. "Because we’re not just purely measuring innings; we’re measuring stressful innings, how hard they’re working in any given outing.”

Minor League reinforcements are there, but not nearly of the caliber of Woo, Miller or Gonzales. Hollander pointed to Tommy Milone, Jose Rodriguez and Darren McCaughan at Triple-A Tacoma, and Emerson Hancock, the club’s first-round pick in 2020 and who began the year with Woo and Miller at Double-A Arkansas.

Hancock is their No. 4 prospect with long-term upside, but the Triple-A arms represent depth rather than reinforcements, at least in the context of a team intending to contend. Which could lead to the grander question of what Seattle does with its fifth rotation spot leading into the Trade Deadline -- and beyond.

Gonzales is confident he’ll be back this season, which would be hugely welcome beyond his health. But given that his timeline is still unclear, that Woo and Miller must be monitored and that other depth isn’t exactly elite, if the Mariners become buyers at the Deadline -- which itself is still not certain given their standing -- it’s possible that a starting pitcher could be added to their shopping list.

“Obviously, we went from a situation where we felt like we were 10 and 12 deep to much less than that now,” Hollander said. “This is sort of the other end of the coin than what we experienced last year where there were no starting pitcher injuries, which is highly uncommon. That's the way it works in baseball.”