Mariners Starting Pitching: 2018 vs. 2017

For the three seasons Jerry Dipoto has watched over the Seattle Mariners’ personnel decisions, the 25-man roster has had its deficiencies, leading to sub par win-loss records, which, let’s be honest, is the only thing that matters at the end of the day.

The starting pitching might be the unit under the most scrutiny the past two seasons, so let’s take a look the club’s rotation performance this season versus last.

To do this, we’ll use basic yet advanced-beyond-traditional statistics, mainly FIP, WAR and WPA.

Why FIP? It’s best used in larger samples, so applying in this instance with basically full seasons under the microscope removes at least some of the doubt of its value. We use it for individual pitchers with some level of confidence, so doing so for an entire club’s schedule should be sufficient enough.

Why WAR? Because without diving eyeballs deep into numerous metrics, WAR is the best cross-metric for FIP. FIP shows us a truer performance. WAR shows us the value.

Why WPA? Because it’s a measure which quantifies how much a performance aided in the team’s chances to win, assigning value to more granular results.

Here’s the Mariners 2018 rotations versus the 2017 group using the three metrics. Number in parenthesis is AL Rank. Note the obvious: Through 137 games in 2018; Full 162 games in 2017.

YEAR FIP WAR WPA
2018 4.13 (6) 10.0 (5) 0.96 (7)
2017 4.98 (12) 6.2 (12) -4.54 (11)

Now, if we want to dig a little deeper, there is further evidence, including strikeout rate, walk rate and innings per start, all which show the advantage to 2018.

Despite the significant improvement from year-to-year, it wasn’t enough. As I write this, the Mariners are 5.5 games out of the No. 2 Wild Card spot with 24 games remaining. And while the bullpen could use a little rearranging and solidifying (the pen ranked No. 6, 6, and No. 5 in FIP, WAR and WPA) and the lineup certainly needs assistance (league-average wRC+) the rotation is the area that can impact the club’s ultimate outcome the most.

Looking forward, the two most meaningful questions are: 1) Is the performance of the rotation the Mariners’ starters put forth in 2018 (through 137 games) true much more than flukey? And 2) What can Dipoto do to add another significant piece before the start of the 2019 season?

The answer to No. 1 is most likely yes, it’s pretty real. Mid-season I think most of us knew Marco Gonzales was due some regressions, and that has happened. I think many expected James Paxton to miss time. That happened, too.

The first half was not sustainable, but the overall body of work certainly appears to be.

The answer to No. 2 is a little more difficult because while we know the names on the free agent list, we don’t know the plans for all 30 clubs, so assessing the markets right now is impossible. That will become somewhat plausible in a month or so as GMs address the media and fans via post mordem press conference.

Among the free agents: Nathan Eovaldi, Trevor Cahill, Gio Gonzalez, Marco Estrada, Patrick Corbin, J.A. Happ, Matt Harvey, Derek Holland, Dallas Keuchel, Charlie Morton, Garrett Richards, Anibal Sanchez, Cole Hamels (opt).

Among those that may be trade-available : Jacob deGrom, Zack Wheeler, Kyle Gibson, Jake Odorizzi.

One thing’s for sure, however: If Dipoto and company can find a way for the rotation to take a similar jump for 2019 as it did for 2018, Seattle will be in a pretty good spot. How they get that done remains to be seen.

 

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Jason A. Churchill

Churchill founded Prospect Insider in 2006 after getting his start at InsidethePark.com. He spent several years covering prep, college and pro sports for various newspapers, including The News Tribune and Seattle PI. Jason spent 4 1/2 years at ESPN and two years at CBS Radio prior to joining HERO Sports in July, 2016. Find Jason's Mariners podcast, Baseball Things, right here and follow him on Twitter @ProspectInsider.

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