Five Mariners storylines we’re watching in the second half

For as underwhelming as the first half of the season was for the Seattle Mariners, all of that could be forgotten with another second-half surge from one of the American League’s preseason favorites to reach the World Series.

Despite having a 48-50 record entering Saturday, they are still just one game out of an AL wild card berth and 1 1/2 games behind the Texas Rangers for first place in the division.

Salk: Mariners will solve a big conundrum at trade deadline

Indeed, all is not lost for the Mariners. But in order to come close to their lofty expectations for this season, they’ll need to play a much better brand of baseball than they did in the first half and in their first game out of the All-Star break on Friday.

With the second half underway, here are some of the biggest storylines we’ll be watching over the final 64 games.

Is there a big move to make at the trade deadline?

The Mariners have been one of the more aggressive clubs at the trade deadline in recent years. They landed Luis Castillo from the Reds in 2022, Randy Arozarena from the Rays in 2024 and Josh Naylor and Eugenio Suárez from the Diamondbacks last season.

Considering where the club currently sits in the playoff race, it still has plenty of reason to push its chips in during a season where the rest of the AL field looks rather weak outside of the Rays and Yankees. But because of that mediocrity in the AL, there’s still several teams who would be clear sellers at this point of other seasons still hanging on to hopes of playoff aspirations.

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That doesn’t mean there won’t be deals to be made, though. The Mariners may have to wait until the final moments for some teams to waive the white flags on their seasons and part ways with impact players. They could also look to other contenders in an effort to swing a rare major-leaguer-for-major-leaguer swap.

If anything, the Mariners should at least be able to bolster their bullpen with a high-leverage arm and add around the margins to improve their lineup. If that’s the case, the next section will be even more important than it already is.

Will big bats wake up?

This Mariners season is starting to have a similar feel to the 2024 squad. The pitching has been great, but the offense just isn’t scoring enough runs. The number one reason for the lack of offensive production is the club isn’t getting what it expected out of most of its big bats.

Cal Raleigh is still trying to get out of a season-long funk. He entered last year’s All-Star break with 38 home runs. He had just 41 hits at the break this year, though some of that can be attributed to missing a month due to an IL stint.

Julio Rodríguez has cooled of dramatically since a promising month of May in which he slugged 10 homers, a career high for a single month. Since June 1, the center fielder has a .327 slugging percentage with just four extra-base hits in 115 plate appearances.

Naylor has also had a disappointing season. After being a catalyst of the team’s 2025 playoff run and signing a five-year contract in the offseason, he has a .671 OPS and minus-0.2 fWAR in 91 games this season. His 96 wRC+ is the fourth-worst among 30 qualified primary first basemen in MLB, per FanGraphs.

Even if the Mariners find a way to add an impactful bat at the trade deadline, they probably won’t go far without this trio performing closer to expected.

Is Luis Castillo a Mariner after Aug. 3?

There’s been plenty of discussion about Castillo and his future in a Mariners uniform. If the Mariners were to trade one the six starters on their 26-man roster before the deadline, the right-hander would seem to be the top candidate. He’s the club’s highest-paid arm and under contract for only one more season after this year.

The question is: Can the M’s get enough in return to make it worthwhile?

After early struggles, Castillo has pitched much better of late. In eight outings (six starts) since May 25, he has a 3.27 ERA and 1.16 WHIP while holding batters to a .228 average. The recent stretch should help bolster his trade value, which certainly took a hit during his rough start to the year, but it also could be a sign the club would be better off shopping one of its arms that could garner more of a return.

With top pitching prospects Kade Anderson and Ryan Sloan knocking on the door for major league promotion, particularly the left-handed Anderson, trading a starting pitcher seems like more of a realistic option than in past years.

Which prospects will impact stretch run?

There’s been an expectation for quite some time now that Anderson will help the big-league club at some point during the stretch run – and for good reason. He’s been phenomenal in his first season of pro baseball, sporting a 1.36 ERA and 0.69 WHIP with 108 strikeouts to 10 walks in 72 2/3 innings at Double-A.

Barring injury, it would be a surprise if Anderson isn’t in Seattle’s bullpen at some point this year.

But will any other prospects have a chance to help the Mariners down the stretch?

There’s been some thought that Sloan could join Anderson in a bullpen role, but that’s not a guarantee considering Sloan is two years younger and hasn’t pitched near as well in Double-A.

Another couple names to keep an eye on are Michael Arroyo and Laz Montes, who were recently promoted to Triple-A. Arroyo in particular appears to have a path to helping out in the majors by seasons end.

This prospect could help the Seattle Mariners this season

Arroyo, a 21-year-old left fielder/second baseman, had an excellent initial showing with Tacoma, batting .333 (10 for 30) with a 1.056 OPS, two homers, two doubles and one triple in his first seven games at the new level. It’s a small sample size and much of it came at the PCL launching pad that is Las Vegas Ballpark, but it’s an encouraging sign nonetheless.

As a right-handed hitter, Arroyo would help address a need for the lefty-bat-heavy Mariners. His ability to play both left field and second base is helpful, too.

When will Brendan Donovan return?

Another culprit of Seattle’s offensive struggles has been the fact that it’s missing its top offseason acquisition and leadoff hitter in Brendan Donovan, who’s been out since mid-May with a left groin muscle strain that has landed him on the IL twice this year.

Donovan was batting .274 with an .838 OPS, three homers, four doubles and one triple in 25 games before his second IL stint. The club could desperately use that sort of production at the top of the order.

The good news? Donovan started his long-awaited rehab assignment Wednesday in the Arizona Complex League and transferred to Triple-A on Friday. However, it isn’t expected to be a quick one since he missed so much time and the Mariners are taking a cautious approach with his injury due the lingering impacts of sports hernia surgery he underwent during the offseason.

Seattle Mariners news and more

• M’s prospect Lazaro Montes crushes HR in 1st home game for Tacoma
• Seattle Mariners share expected timelines on 3 injured bullpen arms
• Salk: Two things need to happen for Seattle Mariners in second half

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