MLB insider offers surprising assessment of what Mariners need most at trade deadline

For weeks, the trade deadline chatter surrounding the Seattle Mariners has revolved around their underperforming offense. However, in a surprising twist, MLB insider Jon Morosi suggested on Seattle Sports that the Mariners should shift their focus elsewhere: starting pitching.

At first glance, this may seem like a misdirection. After all, this is a team that ranks among the league’s worst in several offensive categories and has been desperate for consistency at the plate. Yet Morosi’s point doesn’t go without merit. The Mariners’ starting rotation — a unit long viewed as the foundation of this roster — has quietly become one of the club’s larger question marks.

MLB insider says Mariners’ starting pitching is the real trade deadline problem

Injuries have decimated what was once a formidable group. Logan Gilbert is still working his way back from injury, George Kirby has returned but is not quite all the way back to form, and Bryce Miller continues to bounce on and off the injured list. The rotation’s depth has been tested to its limit, leaving unproven arms like Logan Evans and Emerson Hancock to carry the back end of the rotation. Evans is learning on the fly, while Hancock, despite flashes of promise, remains prone to volatility.

Statistically, the results support Morosi’s concern. The Mariners’ starting rotation ranks 18th in WAR (4.3), 19th in strikeouts per nine innings (8.01), and is tied for 18th in ERA (4.09). These are far cries from the preseason expectations that had Seattle’s rotation projected as one of the American League’s best. For a team constructed around run prevention, the gradual decay of their pitching identity is an issue that can’t be ignored.

If the Mariners are going to make a serious postseason push, they may need to reinforce the rotation before they think about adding a bat. And according to Morosi, one name to watch is Tyler Mahle of the Texas Rangers. Mahle has been quietly excellent in 2025, posting a 2.34 ERA over 77 innings. He’s in a contract year, and with Texas hovering outside the playoff picture, there’s a possibility he could be available. However, the fact that it would be an inter-division trade complicates the matter. The Rangers would almost certainly ask for a steep return from a division rival.

A more practical and intriguing target could be Zac Gallen of the Arizona Diamondbacks. Gallen has had an uneven season (4–8, 5.19 ERA), but he’s a known frontline talent with postseason experience. Arizona is a team on the brink of a soft reset, with several expiring contracts and questions about their long-term roster direction. If the Mariners were bold enough, they could pursue a blockbuster that brings Gallen and an impact bat — perhaps Josh Naylor or even a reunion with Eugenio Suárez — back to the Pacific Northwest.

That type of all-in move would come at a cost, but Seattle has the prospect depth to make it happen. And perhaps more importantly, they have a trade history with Arizona that could help grease the wheels. For a team trying to reclaim its identity as a pitching-first contender, while also fixing a broken offense, a deal like this would check multiple boxes with one swing.

The common belief may still be that Seattle’s biggest need is a bat. But Morosi’s insight offers a timely reminder that without a steady, reliable rotation, even a red-hot offense won’t matter come October.