Andrew Miller is Trending Down

The Cardinals are on the brink of signing Andrew Miller.

The left-handed reliever set baseball abuzz in the 2016 post-season with his high-leverage, non-save situation brilliance. Of course, his breakout into the national consciousness during October was portended by plenty of regular season brilliance starting in 2014. It was the spotlight of the 2016 post-season, and the unique way that manager Terry Francona used him, that gave the rest of the world the chance to see what he could do. His 2017 follow-up had a small blip with a late season knee injury. He was still extremely effective even after coming back from the injury.

Miller was a monster back then. From 2014 through 2017 amongst relief pitchers (minimum 120 innings), Miller ranked:

• first in strikeout percentage
• second in strikeout minus walk percentage
• third in FIP
• first in xFIP
• second in Win Probability Added (WPA)
• sixth in swinging strike percentage (SwStr%)
• second in contact percentage
• third in swinging strike percentage on pitches outside of the strike zone

He was putting up Bugs Bunny numbers from the left side and making hitters look ridiculous. Seriously, look at this. The Khris Davis swing alone should tell you how dominant Miller was:

If the Cardinals signed that guy, we’d all be doing cartwheels. But sometimes, you get a shiny new toy for Christmas and it’s broken. You see, the problem for Andrew Miller is that 2018 happened. The 2018 season saw several startling trends arise. Let’s start with one VEB editor emeritus Craig Edwards shared last night:

Miller has lost between 1 and 2 miles per hour off of his fastball over the last few seasons. The velocity on his slider- one of the most lethal pitches in the game during his dominant run- has also slipped. From Brooks Baseball:

Naturally, these factors have conspired to drag down other peripherals. He had a hard time getting swinging strikes. Last season, his SwStr% reached depths he hadn’t seen since 2013:

Specifically, he’s having a harder time getting hitters to chase outside of the strike zone. His percentage of swinging strikes outside the strike zone was splendid in his peak- 6.7% in 2014, 8.2% in 2015, and 7.6% in 2016. Then in 2017, it slipped to 5.7%. By 2018, it was down to 4.3%.

All of this has led to diminished strikeout percentages and elevated walk percentages:

Predictably, opposing hitters are doing more damage. His opponent weighted on-base average (wOBA) was .218, .210, and .207 from 2015 through 2017. This past year, it was .321.

Before news started to break about Miller last night, I had written a very long article (scheduled for today) about left-handed relief options. The Cardinals clearly need left-handed relief help. I wanted to take a different approach, using Statcast.

I looked for pitchers who racked up lots of swinging strikes, particularly outside of the strike zone. I also wanted to find pitchers who procured lots of contact below 5 degree launch angles- pitchers who forced hitters to beat pitches into the dirt. The ideal lefty would also avoid the danger zone- Zach Gifford’s brilliant Game Power metric. The less frequently a pitcher gave up contact of 95 mph or more at a launch angle of 22 to 38 degrees, the better. And finally, the ideal lefty would possess the ability to get strikes on the edge of the strike zone.

Miller came out on top of those rankings for all lefty relievers from 2017 to 2018. Along with Zach Britton, he was the shiny new toy, the brand name on the market, the Red Ryder BB gun that the Cardinals seemed to crave. However, it quickly became apparent that it was a function of 2017 numbers buoying declines in 2018. His swinging strike percentage was still very solid in 2018 but had slipped. His edge percentage and his chase percentage decreased. On the plus side, he did a better job of avoiding the danger zone, and procured more contact under 5 degrees. He slightly improved his contact profile but gave away a lot of swing-and-miss value while also giving away more free passes.

It’s academic at this point, but Zach Britton- the other lefty monster in the same timeframe as Miller- had steadier numbers. He ranked second in the rankings I’d concocted. Britton has his own concerns, to be sure. But he had fewer than Miller. A lot of other non-brand name lefties had intriguing profiles. Tony Sipp and Luis Avilan, both free agents in the bargain bin, seemed to be low risk/high reward gambles compared to the big names. Aaron Loup and Xavier Cedeno also looked to be calculated gambles, with Loup offering a steadier history and Cedeno the cheaper price.

The irony here is that I’m thrilled that the Cardinals are taking a risk on someone with the upside of Miller. If he’s anywhere near the pitcher he was from 2014 to 2017, he’s pure dynamite in the bullpen. The brand name is exciting. There are many potential reasons for his downturn and not all of them are as nefarious as “He’s cooked.” He fought some nagging injuries each of the last two years and seemed to rebound after returning late this year. Sometimes, pitchers just have bad years, even when they’re over 30. Lefty relievers never die.

Even if 2018 Miller is the new norm and that’s what we see in St. Louis, it’s light years ahead of the goat rodeo the Cardinals had from the left side of the bullpen this year. If that’s what the Cardinals get out of this deal, it’s a win. For that or more to happen, he has to reverse a growing list of troubling trends. Nobody likes a broken toy on Christmas morning.