Mariners Unsung Hero: Hitting Coach Jarret DeHart

Flying under the radar is one man who may be at least partially responsible for the Mariners' august offensive surge.
Seattle Mariners vs. Kansas City Royals
Seattle Mariners vs. Kansas City Royals / Alika Jenner/GettyImages

Sole occupiers of first place in the American League West, it should not come as a surprise that the Seattle Mariners are one of the hottest teams in baseball. Fresh off a sweep of the Kansas City Royals, the Mariners are 9-1 in their last 10 games and 19-5 in the month of August. While pitching has been a particular strength throughout the year, headlined by ace and future aces Castillo, Kirby, and Gilbert, it has been a sudden offensive outburst that has propelled them to their AL-leading August record.

Mariners Team Hitting Stats by Month:































Since August 1st, the Mariners are OPS-ing almost .900 as a team, which for perspective, is roughly equivalent to a lineup of 9 Jose Ramirezes. Ramirez is not having a down season either. The Guardians superstar and perennial MVP candidate enters today batting .279/.353/.489 with an OPS of .842 on the year. For the entire Mariners lineup to be hitting at such a pace for an entire month speaks to the serious offensive firepower this lineup contains.

Such an offensive outburst begs the question: what has changed? While some off the Mariners' hitting improvements can be attributed to personnel changes at the trade deadline, with the new additions of Josh Rojas and Dominic Canzone taking over the at-bats of failed off-season acquisitions AJ Pollock and Kolten Wong, a large part too comes from adjustments and improvements from line-up mainstays like Julio Rodriguez and Teoscar Hernandez.

In the month of August, Julio is rocking an absurd .410/.459/.680 slash with 6 home runs and 27 RBIs. Contrasted with the month of June where he slashed .220/.291/.330, it's quite clear that something has changed. Julio attributes much of his improvement to working with second-year hitting coach Jarret DeHart on small changes to timing and hand placement.

Likewise, other Mariners have also had career months. Teoscar Hernandez, who slashed a measly .200/.248/.286 in the month of July, is now hitting .366/.394/.656 in the month of August. Josh Rojas, who has mentioned working on pulling the ball more with hitting coach DeHart, is OPS-ing over .800 in the month of August and is a large part of the Mariners' offensive successes. While we were quick to blame the Mariners' hitting coach for offensive struggles earlier in the season, it's equally important now to give Jarret DeHart his flowers for the offensive turnaround we've observed.

Just 28 years old, DeHart was a former collegiate baseball player who signed on to be a hitting coach with the AZL Mariners in 2018. After working his way up the Mariners organization, he was promoted to hitting coach after former coach Tim Laker declined to rejoin the club after the 2021 season. In just two years with the Mariners, DeHart has steadily improved hitting numbers, and is currently on track to help the club make October baseball in both seasons.

While the 2023 Mariners started off slow offensively, many of their key hitters have made the necessary adjustments for the recent offensive outburst we've observed. Ironically, the man that's often lost in the shuffle is the same man responsible for working with players on said adjustments. If the Mariners continue to hit the way they do, Jarret DeHart may just end up being one of the most important members of the Seattle Mariners organization.