Chicago Cubs: One year ago, I accurately predicted a Jake Arrieta decline

When I said that Jake Arrieta would continue to trend downward last offseason, I was ridiculed by Chicago Cubs fans. Yet, here we are in such a world.

Let me begin by saying this. I wish I had been wrong. The Chicago Cubs entered 2017 looking to win back-to-back World Series championships. For that to happen, the starting rotation would have to be remarkable yet again. And, as we know now, that simply did not prove to be the case.

Jon Lester posted some of the worst numbers of his career, Kyle Hendricks battled injury before settling in and John Lackey gave up home runs faster than nearly every other starting pitcher in Major League Baseball. Meanwhile, Jake Arrieta continued to trend in the wrong direction heading into his first taste of free agency.

Arrieta ranks as one of my all-time favorite Cubs. His accomplishments are, simply, remarkable. Two no-hitters. 2015 National League Cy Young Award. 20-game winner (the Cubs’ first since Jon Lieber in 2001). His postseason record speaks for itself. And who could ever forget his complete game shutout against Pittsburgh in the 2015 NL Wild Card game?

But, as emotionally attached as many fans are, Theo Epstein and Jed Hoyer made the right call in letting him walk away after the 2017 season. You might not like hearing that, but it’s not an opinion – it’s a fact.

Troubling trends

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Last year, when I wrote the aforementioned piece that had many of you ready to string me up, I pointed to a handful of indicators suggesting things might not rebound. Arrieta’s fastball velocity declined, his off speed pitches were becoming less effective and several mainstream metrics spoke ill of the right-hander’s performance.

One year later, those metrics look even more harrowing.

In his Cy Young 2015 campaign, Arrieta compiled a 1.77 ERA, 2.35 FIP and 11.1 percent swinging strike rate in 229 innings of work. In short, he was outstanding in literally every sense of the word. During the Cubs’ World Series championship run, he fell short of 200 innings pitched, clocking in at 197 1/3 frames, during which he pitched to a 3.10 ERA, 3.52 FIP and 10.5 swinging strike rate.

So, before we even get into the numbers from what was his likely season in Chicago, let’s look at the difference from ’15 to ’16. His ERA jumped by 1.33, his FIP climbed by nearly a run and a half and his swinging strike rate dropped. As troubling as these patterns were, they got even worse last year.

But wait, it gets worse

His innings total again declined in 2017 – dropping down to 168 1/3 from an average of 213 innings over the previous two years. Opponents’ swinging strike percentage dropped like a rock – all the way down to 8.7 percent. Meanwhile, his FIP climbed to 4.16, as did his ERA to 3.53

As much as it pains me to say it, Arrieta seems to be losing his edge- at least to a degree. For the second-straight year, he led the league in wild pitches. His average fastball velocity dropped from 95.2 MPH in 2015 to 92.2 MPH last season, according to Statcast. Not having that mid-90s fastball obviously makes his off speed repertoire less effective – and his hard-hit rate backs that claim up.

During the 2015 run, Arrieta held opponents to a 24.8 percent hard-hit percentage. The number climbed to 29.8 percent in 2016 – again rising to 32.2 percent in 2017. Meanwhile he failed to get hitters to hit the ball on the ground. Remember, part of his dominance in ’15 was his ability and effectiveness when it came to using the Cubs’ elite infield behind him.

That year, he induced ground balls at a 56.2 percent clip. Not too shabby at all. But last season, that fell to 45.1 percent as he struggled at times to show the dominance from years’ past. And, similar to this time last year, PECOTA isn’t a fan of Arrieta moving forward.

Projections again unkind to Jake

Projected for fewer than 150 innings and just 10 wins (although, it’s hardly fair to evaluate someone on wins in today’s game) – the veteran doesn’t seem to fit into the ‘ace’ role by most measures. A 3.68 ERA does not a number one starter make – and that’s what Baseball Prospectus has him pegged for in 2018.

Next: Is this one of the Cubs' best rotations in history?

I will forever be thankful for what Jake Arrieta did in a Chicago Cubs uniform. But letting him walk and moving on with Yu Darvish is a decision that, in five years, will be much more palatable than it is right now. The numbers don’t lie.

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