Biggest deadline trade Mariners didn't make is haunting them from Philadelphia

There are plenty of fingers to point when it comes to the Seattle Mariners' horrendous run of form on the road, with the overriding mantra being that you win as a team and lose as a team. However, at the risk of seemingly 'picking' on a certain area of the roster, it's tough not to notice the struggles of the bullpen in recent weeks no matter where the M's have been playing.

Over the last 30 days, the Mariners bullpen has a 4.85 ERA, which ranks 22nd in the majors. If projected over the course of the entire 2025 season, this would be the third-worst ERA among all 30 teams.

The issues with the M's bullpen over the past 30 days extends to other statistical categories, including ranking 26th with a 1.46 WHIP and dead last with a .279 opposing team batting average. Again if projected over the entire season, they would rank third-worst in WHIP and 30th in opposing team batting average.

Andrés Muñoz highlighting the Mariners' bullpen issues

Almost serving as the poster boy for the bullpen's struggles is Andrés Muñoz, who was quite simply stellar through July and proving himself as one of the best relievers in all of baseball. However, as SoDo Mojo's Jason Wang recently wrote about, the cracks have begun to show since the calendar turned to August.

As of the end of July, Muñoz was sitting pretty with a 1.32 ERA, 2.29 FIP, 0.93 WHIP and .140 opposing team batting average. Since then however, he's produced a 2.92 ERA, 3.38 FIP, 1.46 WHIP and .245 opposing team batting average.

Given all of this, it brings back to mind the only thing the Mariners got wrong at the trade deadline by not acquiring Jhoan Durán. To put it simply, he has been exceptional since arriving in Philadelphia. In fact, he's been even better than when he was still with the Minnesota Twins.

With the Twins this season, Durán had a 2.01 ERA, 2.53 FIP and 1.18 WHIP with 16 saves in 18 opportunities over 49.1 combined innings. With the Phillies, he has taken his game to another level, recording a 1.54 ERA, 0.74 FIP and 0.86 WHIP with 10 saves in 11 tries during 11.2 combined innings.

Caleb Ferguson has been a poor substitute for Jhoan Durán

Suffice it to say the Mariners could use Durán right about now, especially when considering how poor the reliever they did acquire at the deadline has been. Caleb Ferguson has seen his productivity decline since arriving from Pittsburgh, with a 5.25 ERA, 4.39 FIP and 1.667 WHIP in 12.0 combined innings over 15 appearances.

While it's always easier to critique a decision with the benefit of hindsight, the reality is that even at the time there were plenty of people who lamented the Mariners not snagging Durán. He was apparently their top bullpen target, and they were in the running right up until the minute a deal was made for him to go to Philadelphia.

Maybe the Phillies just outright made a stronger offer, but when you consider their package included the 56th and 92nd best top 100 prospects in baseball, you know there was room for the M's to do better. With recent results, it already feels like this has made a difference with the team's playoff push, and not in a good way.