Jack Z has often talked about wanting his teams to be solidly based on pitching and defense. Back when he first joined the Mariners, this seemed like a credible claim... but as the years have gone by, this assertion has rapidly lost traction and is pretty much one big joke at this point. Arguing that defense is a top priority while going out and getting the likes of 40-year-old-Raul Ibanez, Michael Morse, and Mark Trumbo (and then allowing those gentlemen to play hundreds of innings in the outfield) is just bonkers
Luckily for Jack, he has had King Felix on his team for his entire tenure with the Mariners, which has helped him save a lot of face in the "defense and pitching matter!" department. Unfortunately, Felix's struggles this season, combined with the bullpen being SO BAD, have caused the defense/pitching façade to really start to crumble. For the past several seasons, the Mariners have been known as a pitching-first, offense-second team; this no longer feels as though it is the case. To find out how much this dynamic has changed, I've put together the following chart, which shows the percentage of the Mariners team fWAR that has come from pitching/batting for each season in team history.
*Turquoise dots represents the seasons during which the M's made the playoffs.
**The average team over the last 40 years has consistently had ~43% of their team fWAR come from pitching. This average is represented by the horizontal grey line above.
When looking at this plot, it's important to remember that just because a data point is located far from the average, the offense (or pitching) in that season wasn't necessarily good; it could just mean that the pitching (or offense) was especially bad. For example, in 1980, it looks like the pitching staff may have been fairly dominant. But no. They put up a fairly pedestrian pitching fWAR of 13.9 (23rd best in franchise history), but their offensive fWAR was an embarrassingly low 1.7. (I altered the size of the dots to try and aid in the understanding of this chart).
This year, the Mariners are on pace to be the second most offensive-oriented team in franchise history (just behind the 1996 team that had peak Griffey/should've-won-the-ROY-ARod on offense and 63 combined starts from Sterling Hitchcock+Bob Wolcott ). I know that I've made jokes this season after the M's lose a 7-5 ballgame about how this team feels like it'd fit right in with those 90's era clubs that played in the Kingdome, but maybe that statement isn't actually too far from the truth.
The 2015 Mariners are on pace for a combined pitching fWAR of 8.8. That value would be the fifth lowest in team history and the lowest since 2008 (7.9 fWAR) when Miguel Batista and Carlos Silva combined for an ERA of 6.55 over 48 starts. Offensively, the M's are on pace for a batting fWAR of 15.8. This value would be the 20th highest in franchise history (right around the median). Nelson Cruz is likely to make up ~a third of this value and man oh man I don't even want to think about what the Mariners would look like without him this season. So far, his addition has been one of the very best free agent signings in M's history.
At this point, it's definitely inaccurate to refer to the Mariners as a "good pitching team". This season, they have rapidly swung to being a team that relies much more on its offense than it does on its pitching. Unfortunately, this isn't really related to a dramatic uptick in their ability to score runs as much as it has been caused by the implosion of the team's pitching staff. Despite playing in Safeco for half of the season, Seattle's pitchers (especially their bullpen) have struggled mightily. Hopefully this year is an aberration as opposed to the establishment of a new trend. Get it together, Mariners.