Jerry Dipoto's Hail Mary for Mariners bullpen is looking like a work of genius

A few weeks ago, the Mariners made a minor move to pick up some bullpen help in the form of José Castillo. Although he pitched three scoreless innings with Seattle, he was designated for assignment and recently claimed by Baltimore, concluding his brief time with the Mariners.

In Castillo's stead, the Mariners have turned to reliever Luke Jackson, who signed a minor league deal with the team at the end of August. In his brief tenure with the big league club, he's already carving his own niche.

Luke Jackson has exceeded expectations in his new bullpen role with the Mariners

Prior to joining the Mariners, Jackson had subpar results with the Rangers and Tigers, posting a 4.54 ERA and 5.01 FIP for the season. However, in his six outings with Seattle thus far, he has given up just three hits and zero earned runs.

Jackson primarily relies on his slider and four-seam fastball, although he has been known to throw a curveball occasionally. The slider used to be his bread-and-butter pitch, but his fastball has quickly been elevated to his weapon of choice.

His heater sits around 94 mph, slightly below league-average, but what has made it an effective pitch this season is its 18.4 inches of vertical break. This is on the higher end of fastballs in the big leagues (the IVB on Bryan Woo's four-seam fastball is just 14.9 inches) and this gives the ball more of a rise effect, making it harder to hit even if it's not blowing by opposing hitters.

Although Jackson's fastball has a whiff rate of just 13.4 percent, opposing hitters are averaging just .174 and slugging just .261 against the pitch. He has thrown it more frequently since joining the Mariners, bumping the utilization up from 31.4 to 46.5 percent.

Soft contact has been the key to his success over the past few weeks. He has a barrel rate of just 5.3 and a hard-hit rate of 36.8, marked improvements over what he has done over the whole season. He has continued to get hitters to roll over while cutting down his walk rate to just 7.7 percent, limiting traffic almost entirely and giving him a WHIP of just 0.71 as a Mariner.

As of now, Jackson has elevated himself to a key role in Seattle's bullpen. He has played an important role in their recent win streak that has fueled their push towards division and postseason glory. Hopefully, his success will continue through the remainder of 2025, but it's difficult to make such a claim with any certainty for any reliever, much less one that has struggled to find a long-term home for the past two seasons.

So far, he's doing all the right things and this minor league deal seems like a winning lottery ticket. Let's just hope things don't fall apart at the wrong time.