The second part of this terrible season kicks off against a Mariners team that’s straining to match their success from a year ago. Those 2025 Mariners? AL West champs. Cal Raleigh hit 60 dingers and they were 4th in the AL in runs scored to boost a decent pitching staff. These 2026 Mariners? 1.5 games back of the division and never more than 4 games over .500. Cal Raleigh? Just 9 homers and one of the worst regulars in the entire sport. They’re 12th in the AL in runs scored, 26th in MLB. Meanwhile,
the Giants are playing for 2028 and beyond, when their highly regarded farm system should start producing results.
(Seriously, go listen to Roger’s There R Giants podcast with MLB Pipeline’s Jim Callis.)
So, rather than delve into the hows and whys of these two disappointing teams, let’s do some trade talk about a trade that will almost definitely not happen. In looking at potential trade partners who could take on some of the Giants’ bigger contracts, I’ve conceded that at the end of the day the Giants would have to do contract swaps; and, given that Zack & Buster will need to once again rebuild the rotation for next season (or post-lockout) following Robbie Ray’s departure, a contract they should probably take on is one of a veteran pitcher just to guarantee themselves some innings. And that led me to two names: Philadelphia’s Aaron Nola and Seattle’s Luis Castillo.
But the thing is, Aaron Nola’s contract runs through 2030 and his age-37 season while Castillo’s runs through 2027 unless he pitches 180 innings in which case it vests for 2028. Now, there’s a decent chance of a lockout so that vesting option would seem to be unimportant, but the Mariners seem like they’re doing an annual dance with their payroll and probably want to ditch a pitcher they have already shuffled away from the rotation.
Could the Giants use their former prospect to stanch the bleeding they’re likely to face here over these final 66 games and however many games are played in 2027? I don’t see why not. Although Castillo has been on a steady decline since his age-28 season of 2021 with the Reds — 3.9 fWAR then followed by 3.7, 3.3, 2.3, 2.6, and a projected 1.5 this season — he still has a lot of qualities that could help the Giants’ rotation. They are:
- Two fastballs — a four-seamer and a sinker — which both average 95 mph (65th percentile)
- A 7.2 BB% (70th percentile)
- A 20.8 K% (37th percentile)** — hold on, this low value is still a positive and I’ll explain in a moment.
- Innings eater (2023-2025: 197, 175.1, 180.2)
Yes, he’s in clear decline. He averaged 97 mph with his fastball from 2020-2022, then 96 2023-2024, and he’s down to 95 the past two seasons, his strike rate through age 30: 9.86. Ages 31-33: 8.48.
He’s not the pitcher he once was and he’s due to make $24.15 million next season (and 2028, if the option vests). That’s less than what Robbie Ray is scheduled to make here in his final season with the Giants (his age-34 season, which is what Castillo’s age would be in 2027) and it carries a lower Competitive Balance Tax number because of the annual average of his 5-year, $108 million deal he signed after the Mariners traded for him: $21.6 million.
We don’t know what the CBT will look like in the new Collective Bargaining Agreement, of course, but if the Giants aren’t going to move Logan Webb (which they should) then they’ll need to add to the rotation until the next competitive window opens. But rather than pay today’s free agent market prices for pitching, taking on contracts valued from a previous generation makes a lot more sense.
Plus, the Giants can begin to make amends for the Casey McGehee trade.
Now, a trade like this would probably require a third team, because it’s hard to imagine the Mariners trading for Robbie Ray after trading him away, but being a pass-through for another team who needs a pitcher like Ray?
According to this MLB.com article, the Mariners need a right-handed bat and a proven reliever. The Giants, of course, don’t have a proven reliever, except for maybe Caleb Kilian, who has been great in any inning that’s not the 9th inning (seriously, look at these splits); but, better yet, they have a really solid right-handed bat option in Heliot Ramos.
So, on the one hand, you could see the Giants being willing to send Robbie Ray to the Mariners for Luis Castillo and a prospect or two (16 of Seattle’s top 30 are pitchers, btw) and you could see the financialization model Jerry Dipoto seems to swear by motivating the Mariners’ side (they get out from the 2027 commitment to Castillo), but in order for it to really give Seattle what they need (financial flexibility), you could see them needing a bit more.
Would Matt Chapman want to live in Seattle for half the season? That could be another possibility if the Mariners want to actually use their financial flexibility to make a bigger splash. I don’t think T-Mobile Park is a good fit for Chapman, of course, but Seattle’s contributions from third base this season have been dire: a 75 wRC+ and -5.4 Defensive Runs Above Average. Hard to see Seattle trading into a long-term deal for a player in his (at least, when tracking age to history) decline phase, but I admit I’m having a hard time figuring out who that third team would be in this trade pitch of:
Giants receive
SP Luis Castillo
2 Mariners prospect (Teddy McGraw & Jared Sundstrom?)
1 Team #3 prospect
Mariners receive
OF Heliot Ramos
RP Caleb Kilian
1 Team #3 prospect (which goes to the Giants)
Team #3 receives
SP Robbie Ray
Anyway, that was a lot more fun than going through the actual series. With maybe 30 more wins left in their schedule, let’s maximize the entertainment value in the time we have left.
Series Overview
Who: San Francisco Giants (41-55) at Seattle Mariners (48-49)
Where: T-Mobile Park | Seattle, Washington
When: Friday at 7:10pm PT, Saturday at 5:08pm PT, Sunday at 1:10pm PT
National broadcasts: Fox TV (Saturday)
Projected starters
Friday: Landen Roupp (RHP 6-8, 4.27 ERA) vs. Bryce Miller (RHP 4-3, 2.18 ERA)
Saturday: Logan Webb (RHP 5-7, 3.86 ERA) vs. Bryan Woo (RHP 7-6, 4.23 ERA)
Sunday: Robbie Ray (LHP 8-6, 3.38 ERA) vs. Logan Gilbert (RHP 7-6, 3.32 ERA)
Players to watch
Mariners
Julio Rodriguez: He’s expected to come off the concussion IL during this series after missing basically all of July. He wound up there after taking a throw off the back of his helmet during a double play. Ouch. The 25-year old hit .267/.324/.474 with 32 homers and 30 steals last year, but this year, he’s down a bit to .259/.323/.427 and just 14 homers and 12 steals. Now, it’s entirely possible that he kicks off the second part of the season with a bang and goes on a tear that brings his 2026 season line closer to his final results in 2025. The Giants seem like the perfect team to get him going.
Logan Gilbert: Since giving up 7 runs to the Padres back on May 16th, he’s got a 2.20 ERA (2.35 FIP) over his last 9 starts with a 5:1 strikeouts to walks ratio in 57.1 IP. The Mariners are 7-2 over this stretch, the only two losses coming on the road, when the Guardians & Rays both scored 4 off of him.
Randy Arozarena: Since June 1st, he’s hitting .279/.395/.471 with 5 homers, 5 doubles, and 19 RBI. His season line of .286/.380/.458 has him on pace for the best season of his career. Remarkably, he’s just 9-for-51 (.176) in his career against the Giants.
Giants
Rafael Devers: I can’t remember where I saw it so plainly stated, but it was, essentially, that despite the Giants and Mariners being very similar organizations, right down to the pitcher’s park quality of their home stadiums, there was one key difference in that regard: righties hit better in Oracle Park and lefties hit better in T-Mobile Park. So, it was with that in mind that I went straight to Devers’ split and lo! In 21 career games (95 PA), he’s slashing .298/.379/.560 with 6 homers and 4 doubles. He also has 3 stolen bases. You know, since the 1-year anniversary of the blockbuster trade, after every pundit put on his critical hat to say how much of a flop it had been, he’s hitting .298/.400/.702 with 10 homers and 15 walks against just 18 strikeouts in his last 100 plate appearances. L. O. L.
Bryce Eldridge: He was 6-for-24 on the homestand, but it felt a little quiet. He was 6-for-24 on the last road trip, too, and that felt a little quiet. 12-for-48 with a pair of homers, a pair of homers, and just 6 walks isn’t what we had in mind, I’m sure, so let’s see what he does against the three best starters in Seattle’s rotation.
Logan Webb: His July is canceling out his stellar June and rekindling the thought that his best days are behind him. He’s 0-1 with a 5.29 career ERA in 3 starts against the Mariners, but the only time he’s started a game in T-Mobile Park was 2021. Personally, I’m sticking to GPT’s simple assessment:
The Giants’ pitching system has created a series of Logan Webbs. Can the real Logan Webb distinguish himself again?
Prediction time
The Giants will not trade for Luis Castillo.
