Monday moves: Giants sign RHP Luke Jackson, trade for LHP Erik Miller

Today, the San Francisco Giants announced that they’d signed reliever Luke Jackson to a 2-year deal and traded for left-handed reliever Erik Miller from the Philadelphia Phillies. Both arms figure to improve the 8th-worst bullpen in the National League.

Righty Luke Jackson’s deal also has a club option for 2025. Evan Webeck of the Mercury News with the details:

#SFGiants in agreement with RHP Luke Jackson. 2 years, $11.5M w/ club option for 2025. Jackson missed 2022 after Tommy John surgery but posted a 1.98 ERA in 71 games w/ ATL in 2021.

That $5.75 million AAV is one of the larger deals Farhan Zaidi has handed out since taking over the Giants’ baseball operations and is much more than the usual $1.75-$2.5 million he’s been willing to do with relievers up until the Taylor Rogers signing last month. The difference here is that Jackson was a free agent, whereas most of the players the Giants have used in their bullpen have been under some sort of team control. A perfect example of this is John Brebbia.

John Brebbia 2.0 is a great way to look at Luke Jackson, by the way. Brebbia was designated for assignment by the Cardinals and rehabbing from Tommy John surgery. The Giants signed him as a free agent before the 2021 season and basically helped him rehab (18 games in MLB, 4.59 FIP) and get back into shape in order to brutalize him in 2022 (76 games, 3.32 FIP). Jackson ought to be completing Tommy John rehab in 2023 — he had the surgery on April 13, 2022.

I dismissed Jackson out of hand last month when I did a rundown of relievers the Giants might target specifically because of the TJ thing. I will be sure to be a little more careful with my mental model when discarding players based on what I think I remember about the Giants’ behavior. He fits perfectly, especially with the John Brebbia sitting right there. If I hadn’t been so thoughtless, I would’ve pointed out that he has the 95+ mph fastball and 2500 rpm slider spin the Giants use as a barrier for entry into their pitching lab/bullpen.

A glance at his Statcase page shows a big jump in slider spin rate between 2018 and 2019, and — oh look! — this article explains it:

Gyroscopic sliders are a good fit for a pitcher like Jackson because they work around the inability to naturally spin a baseball over 2,800 rpm. (The average slider in 2019 has around 2,400 rpm; Jackson’s has around 2,500 rpm.) And spinning a baseball is something pitchers can’t easily tinker with unless using a foreign substance. “We don’t know what totally creates spin,” Hezel says.

If a pitcher throws a more horizontal slider, a high spin rate can help the pitch move, leading to a greater chance of producing swing-and-miss. Average-spin pitchers like Jackson, then, need to get creative. “The gyroscopic slider is basically just a shortcut to kill lift and get movement because you’re having a hard time creating movement yourself,” Hezel says.

I bolded the foreign substance sentence because it popped out at me and when I went to look at Jackson’s Statcast for 2021 — MLB started cracking down on June 21, 2021 — I see that his slider spin rate did decline into the 2300 rpm range, but that didn’t stop him from having a great season by reliever standards (1.98 ERA in 63.2 IP, 71 appearances, despite a 3.66 FIP). He also pitched in 11 of Atlanta’s 16 postseason games on their way to the 2021 world championship.

2021 marked a career highpoint for the then-29 year old. Before that slider renaissance, he was a standard reliever — a 91 ERA+ / 4.05 FIP guy. Someone who would more comfortably fall into that league minimum to $2.5 million range the Giants had focused on before. The Giants will need him to carry over whatever improvements he made in that lab and through Tommy John rehab. If Brian Bannister’s pitching lab can survive the recent departure of Matt Daniels, then they’ve got a guy in Jackson committed to maintaining or outright improving through pitching science. A hard-throwing righty is just what the bullpen needs.

That’s because the Giants have ditched their last remaining hard thrower who isn’t Camilo Doval. Yunior Marte and his 97+ mph fastball heads to Philadelphia in exchange for lefty prospect Erik Miller, the Phillies’ 4th round draft pick in 2019 and their #7 prospect according to MLB Pipeline. And, he’s a Stanford grad!

MLB Pipeline says:

[...] a shoulder issue limited him to just 12 2/3 regular season innings in 2021, though he was able to make six relief outings in the Arizona Fall League.

A legitimate three-pitch mix gives Miller the chance to start, though he spent most of 2022, and reached Triple-A, pitching out of the bullpen. He tends to sit in the low-90s with the fastball, though he’s up to 97 mph, especially in shorter stints. He’s always had a very good changeup, killing spin with it effectively, and he’s worked to tighten up his breaking ball, a low-80s slider that can miss bats.

The biggest thing holding Miller back, other than arm health, is his ability to throw strikes.

As tantalizing as the starting prospect sounds, he reads a lot more like a left-handed power reliever. Think less Sammy Long 2.0 and more Jake McGee 2.0 (whom, you will recall, was excellent in 2021 with the Giants and prior to that, had a successful 6-wins across six seasons run with the Rays).

I’m a big believer in power in the bullpen, an area the Giants lacked, particularly from the left side. Getting Miller for Marte is an intriguing no-cost potential upgrade there . Losing Gregory Santos and Marte — even with their command issues — means the Luke Jackson deal has to hit just based on the cost and questionable depth there (Mason Black and Will Bednar?). The deal works out if, come May or June, he’s become that third or fourth reliable arm in the pen after Doval, (Ta.) Rogers, and Brebbia.

Even if that doesn’t happen, the Giants managed to add a bit of experience to their reliever corps — which they badly needed — and some high upside raw material to their high minors — which they needed even more. The 2023 Giants got a little bit better.