Mariners have their work cut out for them with new LHP covered in red flags

The Seattle Mariners needed another bullpen option, and specifically one of the left-handed variety. As such, their depth chart is better after they added Josh Simpson in a trade with the Miami Marlins on Monday.

Well, it wasn't so much a "trade" as a "purchase." The 28-year-old is coming from Miami in exchange for cash considerations, as the team itself reported.

And now for the bad news: While you can squint and see things on which the Mariners might be able to work some magic, Simpson isn't the most inspiring acquisition.

He made his major league debut last year and ended up with a 7.34 ERA to show for 31 appearances. He also has a 4.33 ERA for his career in the minors, with a common problem at all levels being the free pass. He's walked 4.4 batters per nine innings as a minor leaguer, and he issued 22 walks in just 30.2 innings as a major leaguer last year.

Even the Mariners might have a hard time fixing Josh Simpson

To be fair, the Mariners have earned the benefit of the doubt when it comes to seemingly unspectacular relievers.

Andrés Muñoz, Matt Brash, Gabe Speier and Eduard Bazardo were not hyped prospects once upon a time, yet Seattle's pitching lab has turned all four into upper-level bullpen arms. They now hope to do the same with Jose A. Ferrer, and the plan isn't even that complicated.

For his part, Simpson checks a big box in that he has good stuff. He sat at about 94 mph with the four-seamer and the sinker last year, with a sweeper that drew a 40.3 whiff rate and a curveball that was hit for only seven singles in 31 at-bats.

And yet, there are the walks. That's where Simpson is an odd fit for the Mariners, who prioritize strike-throwing even from their relief corps. In 2025, the team's bullpen tied for the fifth-lowest walk rate in the league.

Further, Simpson gave up five home runs even in his limited major league action last year. Left-handed batters actually hit three of those, which was consistent with his performance at Triple-A Jacksonville. Of the six homers he gave up in 34.1 innings, four were hit by lefties. In all, four of the seven left-on-left homers he gave up came off the sweeper, which can catch too much of the zone.

Whatever plan the Mariners have for Simpson, the bright side is that they have plenty of time to let it play out.

He's functionally the last man on the 40-man roster, as Logan Evans was placed on the 60-day injured list to clear a spot. He's one of eight reserves (all of whom have at least one minor league option remaining) beneath the hurlers projected to make the bullpen out of spring training, and the second lefty in line after Robinson Ortiz.