BRANDON GUSTAFSON

Who 5 of Mariners’ biggest X-factors in 2024 are

Mar 9, 2024, 9:58 AM | Updated: 10:00 am

The Seattle Mariners enter 2024 with high hopes after missing the playoffs last year thanks in part to a disappointing end of the season.

ESPN’s Olney: Seattle Mariners have many thinking they can win AL West

The M’s have plenty of familiar faces on the roster that will be key to any success this year, such as Julio Rodríguez, J.P. Crawford and Cal Raleigh on the hitting side, as well as a trio of top-end starting pitchers in Luis Castillo, George Kirby and Logan Gilbert. They also made a big splash in free agency with Mitch Garver, who profiles as Seattle’s cleanup man and everyday designated hitter.

So who are some X-factors who will be vital in 2024 that maybe aren’t being talked about enough?

A few names stand out as players who can dramatically impact the team’s floor and ceiling, even if they’re maybe being overshadowed by others on the roster.

Let’s break it down.

Difference makers for 2024 Seattle Mariners

Outfielder/first baseman Luke Raley

The addition of outfielder Luke Raley from Tampa Bay was overshadowed a bit as the news came shortly after the M’s re-acquired Mitch Haniger from San Francisco on the same day. But don’t sleep on Raley by any means as he could very well be a glue guy for the Mariners in 2024.

Raley, 29, finally got consistent MLB playing time in 2023 for the Rays, and the left-handed hitter made the most of it.

In 118 games, Raley slashed .249/.333/.490 (.824 OPS) with 45 extra-base hits, 19 home runs, 49 RBI and 14 steals in 406 plate appearances. The bulk of those appearances (363) were against right-handed pitchers, whom Raley hit .247/.337/.497 (.834 OPS) against with 17 of his 19 homers.

In a very small sample against lefties (43 plate appearances), Raley slugged two homers with a .268 batting average and .741 OPS.

If Raley is indeed going to be more of a platoon bat, that still means we’ll be seeing him quite a bit.

The Mariners had 4,577 plate appearances against right-handed pitchers last year compared to 1,624 vs lefties. The M’s saw at least one right-handed pitcher in 160 games compared to seeing southpaws in 125 games.

For Raley, a key for him if he does get as much playing time as anticipated is finishing strong.

He got off to a hot start last year, posting a .270/.352/.574 (.925 OPS) line with 15 homers in 70 games played in the first half. The second half was more of a struggle as he hit only four home runs and slashed .219/.307/.370 (.677 OPS) in 48 games. He had OPS marks of .662 and .630 over the final two months of the year, well below the MLB average.

Raley is an aggressive hitter, as evidenced by him walking just 28 times in 2023, but that worked out well last season. He had a .972 OPS when swinging at the first pitch and 1.527 OPS when putting the first pitch of an at-bat in play. When he took the first pitch, he had a .730 OPS mark.

The Mariners’ most important hitters are Rodríguez, Crawford, Garver and Raleigh, but Raley could be the key to making Seattle’s lineup longer if he’s able to put up numbers comparable to last year while hitting somewhere in the 6-8 range in the lineup. He also gives the M’s insurance at first base, too.

Second baseman Jorge Polanco

Jorge Polanco comes to Seattle from Minnesota after a very solid career with the Twins.

It may be cheating a bit to say that the No. 3 hitter is an X-factor and not in the same category as Rodríguez, Crawford, Garver and Raleigh, who will all be hitting right around him in the lineup, but Polanco is the guy who can really make the M’s lineup go and work.

Polanco, 30, will be Seattle’s everyday second baseman, and he owns a career .269/.334/.446 (.780 OPS) slash line.

Part of his appeal isn’t just that he addresses a clear position of need for Seattle, but that he’s a switch-hitter with pop from both sides.

He’s hit .269 both right- and left-handed and has power from both sides of the plate, but he gets on base more (.348 on-base percentage) hitting lefty compared to .305 hitting right-handed.

Polanco has dealt with injuries in recent years, with lower-body concerns limiting him to only 80 games in 2023. He still did have a nice year statistically with a .255/.335/.454 (.789 OPS) final line.

In his last full season played in 2021, Polanco put up big numbers to the tune of a .269/.323/.503 (.826 OPS) slash line with 33 homers and 98 RBI in 152 games played.

Polanco will be offering some much-needed protection for Rodríguez, an aggressive hitter who will at times get into funks with swing-and-miss or recording outs early in counts. Polanco will also be able to hit with the speedy Rodríguez on base quite a bit, which won’t be enjoyable for opposing pitchers.

Polanco is a veteran hitter who has an above-average career walk rate, and his career strikeout rate is just 18.1%, below the MLB average of 22.1% last season. The Mariners had a well-documented issue with strikeouts last year, so having a middle-of-the-order bat who puts the ball in play consistently is much needed as Seattle enters 2024.

If Polanco can stay relatively healthy over 162 games, he can play a big role in the Mariners potentially returning to the playoffs.

Starting pitcher Bryce Miller

Between Castillo, Kirby and Gilbert, the Mariners have as good of a top three in their rotation as there is in MLB. Two youngsters have the M’s feeling good enough to roll into 2024 with them as parts of the rotation, as well.

Those two are right-handers Bryce Miller and Bryan Woo.

Both debuted last year and are set to enter their first full season in MLB, and the duo has some of the same questions to answer this year.

I pick Miller over Woo when it comes to being an X-factor since Miller is more likely to stick in the rotation and make every start, as Woo has some injury and durability concerns dating back to his college years.

Miller was the first of the two to debut in 2023. In 25 starts, he had a 4.32 ERA with 119 strikeouts in 131 1/3 innings along with an 8-7 record.

A big key to Miller’s 2024 season will be his ability to get left-handed hitters out. Lefty hitters dominated Miller to the tune of a .303/.358/.558 (.917 OPS), while he owned righties, who had a lowly .549 OPS off him.

Miller was extremely fastball-heavy last year, especially to start his MLB career. He worked in more breaking balls later in the year, and he now has a weapon in a splitter in order to help him with his lefty problem. The early results of that pitch have been very promising.

Related: Bryce Miller unleashes his splitter in spring training

If Miller takes a good step forward and remains durable, the Mariners very well could cement themselves as having MLB’s unquestioned top rotation. Miller remaining a good, reliable starter is especially important due to Woo’s durability concerns, the fact that pitching prospect Emerson Hancock has struggled to stay healthy since being drafted in 2020, and because Seattle traded veterans Robbie Ray, Marco Gonzales and January acquisition Anthony DeSclafani this offseason.

If you had a crystal ball and could see what Miller’s 2024 numbers end up looking like, you probably would also have a good idea of how the Mariners will finish this season.

Reliever Gregory Santos

The Mariners gave up quite a bit to acquire hard-throwing reliever Gregory Santos from the Chicago White Sox and make him a key fixture of their bullpen.

Santos will still be an important arm for Seattle, but his importance has potentially increased a bit of late.

Matt Brash is working his way back through an elbow injury, and while it doesn’t sound like Brash will miss as much time as initially feared, he may not be ready for opening day. The wild card with Santos, though, is he also is working his way back from injury and may not be ready by opening day. But Santos is further along than Brash as he threw a bullpen session on Friday. The Mariners also signed veteran reliever Ryne Stanek on Friday as insurance to the bullpen.

As such, Santos has a chance to be one of Seattle’s top three relievers both with Brash in the mix and without.

There’s a ton to like with the Mariners’ new 24-year-old right-hander.

He appeared in 60 games for the White Sox last year, finishing with a 3.39 ERA and 2.65 FIP with 66 strikeouts to 17 walks. He also only gave up two home runs.

Santos is one of the hardest-throwing pitchers in baseball, with his sinker sitting at 98.8 mph, which ranked in the 98th percentile in MLB per Statcast.

There’s even more under-the-hood data that shows how effective of an arm Santos was in 2023 and can be moving forward.

His chase rate (33.5%) was in the 91st percentile in MLB, and his whiff rate of 30% was in the 77th percentile. And while many hard-throwing relievers struggle with walks, Santos stayed in the zone with a 5.9% walk rate, which was in the 85th percentile.

Santos also excelled at limiting hard contact, as he was in the 100th percentile in opponent barrel rate and 78th percentile in hard-hit rate (95 mph or better exit velocity). Santos keeps the ball on the ground with a 52.2% groundball rate, which was 87th percentile.

Like most relievers, Santos uses a two-pitch mix. His slider, as with Muñoz and Brash, is the main attraction.

Santos used the breaking ball over 52% of the time in 2023, and the results were stellar. Opponents hit just .196 off it with a .203 slugging percentage. He picked up 48 of his 66 strikeouts with the slider, and of the 29 hits off the pitch, only one was for extra bases (it was a double). Opponents swung and missed at it 37.5% of the time.

As for the sinker, the velocity was good, but opponents did have some success off it, hitting .339 with a .477 slugging percentage, but that was a big part of his ability to induce groundballs.

If Brash does indeed pitch this year (and signs have been positive over the last week), he will be a key leverage arm. But Santos will be big immediately for an M’s team that has leaned heavily on the bullpen over the last few years.

Seattle Mariners first base prospect Tyler Locklear

If any hitting prospect is going to make an impact this year, it will either by Tyler Locklear and/or Ryan Bliss.

It very well may be Bliss, but Locklear could factor in to the Mariners’ lineup in a major way.

Morosi on Mariners: Why Ryan Bliss is a potential rookie to watch

Locklear, Seattle’s second-round pick in 2022, was a third baseman in college but plays first base in the M’s farm system.

He had a massive career at VCU, where he slugged 37 homers with an absurd 1.217 OPS in 132 games over three years. And since joining the Mariners organization, he’s hit everywhere he’s gone.

In 61 games for High-A Everett last year, Locklear slashed .305/.422/.549 (.971 OPS) with 12 home runs, 44 RBIs and and 31 extra-base hits while drawing 36 walks to 60 strikeouts.

That performance was enough for him to finish 2023 at Double-A Arkansas, where after a slow start he wound up with a very respectable .260/.383/.403 (.786 OPS) slash line with eight extra-base hits, one home run and 8 RBIs across 22 games.

Locklear has a ton of offensive upside and has a chance to be a true middle-of-the-order, run-producing bat as a long-term option at first base. He also adds valuable insurance for the Mariners when it comes to two key bats.

First baseman Ty France had a poor 2023, leading to him changing his body and swing at Driveline this offseason. If those changes don’t pan out, Locklear is on the cusp of debuting. The team has not been shy to promote bats and arms alike straight to the big leagues from Double-A, which is where Locklear likely begins 2024.

The M’s also signed Garver to be the team’s everyday DH. The 33-year-old Garver has an extensive injury history, but that also was due largely to him being a catcher. With him not likely to catch much – if at all – in 2024, the hope is he can stay healthy. But if something does happen, perhaps Locklear becomes an option as the team’s DH if Seattle doesn’t want to give that role to one of its trio of corner outfielders.

More on the Seattle Mariners

• Mariners Odds & Ends: MLB The Show ratings, uniform notes and more
Mariners Notebook: Some standouts plus a tip of the cap to Zunino
• Drayer on Logan Gilbert’s outing, M’s highlights and more
Which Seattle Mariners stood out in first week of spring training games?
• Why Seattle Mariners’ Julio Rodríguez-Ichiro connection is so valuable

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