Heading into the offseason, the Seattle Mariners are focusing on bolstering their bullpen, an area identified as a critical positional need. Despite expectations for improvement in 2024, the depth of the relievers remains a concern. The team is optimistic about Matt Brash’s recovery from Tommy John surgery, which is ahead of schedule and expected to see him return early in April. Gregory Santos is also anticipated to be fit after a challenging previous season filled with injuries.

Recently, the Mariners added Shintaro Fujinami to their roster and further strengthened their bullpen by acquiring right-handed reliever Will Klein from the Oakland Athletics in exchange for international slot money, effectively adding him to the 40-man roster. In a corresponding move, left-handed reliever Tyler Jay was designated for assignment. Klein, initially drafted by the Kansas City Royals, had a rocky MLB debut last season with a 6.35 ERA in five appearances, followed by a difficult stint with the Athletics where he posted a staggering 27.00 ERA over three games. While Klein's initial statistics are concerning, the Mariners are known for their capability to develop pitchers, suggesting they might extract better performance from him.

The Seattle Mariners have signed veteran reliever Neftali Feliz to a minor-league contract, providing much-needed bullpen assistance. Feliz, a former AL Rookie of the Year and All-Star, has a notable history with the Texas Rangers, where he achieved significant success in 2010.

At 36, Feliz has not pitched in the majors since 2021 but is currently performing well in the Dominican Winter League. This low-risk signing aims to bolster the Mariners' bullpen after recent departures.

The Seattle Mariners are currently participating in the MLB Winter Meetings in Dallas, focusing on potential acquisitions, including Japanese star Roki Sasaki. However, they have yet to make any significant moves.

In a notable development, veteran reliever Yimi Garcia has returned to the Toronto Blue Jays after signing a two-year contract worth $15 million. Garcia's tenure with the Mariners was marred by injuries, limiting his effectiveness.

Despite the setback with Garcia, the Mariners have opportunities to strengthen their bullpen, especially with the return of Matt Brash from surgery and the potential emergence of top prospect Brandyn Garcia in the future.

The Seattle Mariners finished the 2023 season with an 85-77 record, narrowly missing the playoffs for the second consecutive year, largely due to offensive struggles and bullpen issues.

Key reliever Matt Brash underwent Tommy John surgery, while Gregory Santos also faced significant injury setbacks. Despite mixed performances from other relievers, the Mariners hold hope for a stronger bullpen in 2025, especially with Brash's potential early return.

Brash, who had a strong 2023 season, is recovering ahead of schedule and could be back by late April, providing the team with much-needed stability.

The Seattle Mariners are facing critical roster decisions ahead of Opening Day 2025, particularly regarding their infield and bullpen. President of Baseball Operations Jerry Dipoto and General Manager Justin Hollander have emphasized the need for infield improvements, while recent non-tenders have created gaps in the bullpen.

New minor league signings like Yunior Marte and Adonis Medina may compete for major league spots, alongside recovering pitchers Gregory Santos and Matt Brash. Notably, top prospect Brandyn Garcia, who excelled in the minors, could transition to a reliever role in 2025, adding intrigue to the Mariners' spring training.