Can Dallas Keuchel bounce back?

Although their trade for Chris Sale has made them the favorites in the American League, an argument can — and has been — made that the Red Sox are not the team that’s experienced the most improvement this offseason. That superlative, rather, should probably go to the Houston Astros.

Part of the reasoning here is the fact that Boston was already probably the best team in the AL in 2016. Despite David Ortiz’s retirement, the addition of Sale just maintains the status quo in many ways. The Astros, unlike Boston, did not lead the league in runs scored, win 90+ games, or make the playoffs.

Houston finished 84-78 — good, but not great — and both its BaseRuns and Pythagorean records suggest it just about played to its 2016 talent level. After a surprise playoff run with a young team in 2015, that probably felt like a disappointment to those inside the organization.

The team's moves so far this offseason suggest that the regression they showed in 2016 will be a one-year blip. By adding guys like Carlos Beltran, Josh Reddick, and Brian McCann, the Astros have committed to winning big in 2017 — perhaps making that infamous Sports Illustrated cover look prescient after all. Factor in improvement and/or full seasons from guys such as Carlos Correa, Alex Bregman, and Yulieski Gurriel, and you can see why nobody is going to want to play this team.

Yet while their lineup looks absolutely devastating, the Astros aren’t going to be able to reach juggernaut status if they can’t back it up with good pitching. And while Charlie Morton is an interesting signing for the back end of the rotation, improvement will have to come from within.

Yes, Lance McCullers and Colin McHugh are already quite good and could get even better. But more than anything, Houston has to be hoping for more from Dallas Keuchel.

The 2015 Cy Young winner had a season from hell last year. His ERA was 4.55, higher than it's been since 2013, the year before he broke out. His walk and strikeout percentages both dipped significantly. His BABIP went up 35 points. Oh, and he was shut down for the season in August with a shoulder injury.

Now, if you’re an optimist, you’re probably going to say he got unlucky and write his season off as a fluke. We just talked about his BABIP spike, and we know how random BABIP can be. Perhaps you’ll look at his FIP (3.87) as compared to his ERA (4.55) and point to that as evidence that Keuchel was in fact pretty good rather than kind of bad.

And maybe you’d be right. We won’t have any indication whether that’s right or wrong until Keuchel has made several starts in 2017. But 2016 was undoubtedly a discouraging season, and the reasons why aren’t very hard to find.

If you’re in any way familiar with the approach that made Keuchel a star in the first place, you know that he operates in a different way than the stereotypical “ace.” Kuechel is not Noah Syndergaard blowing opponents away with otherworldly stuff. He’s finesse and command. His 2015 season goes down as one of the greatest seasons ever by the soft-tossing lefty archetype.

Obviously, that approach can be extremely effective. Keuchel has proven that. But it also provides less room for error. Aroldis Chapman can miss his spot and get away with it because he’s throwing 101. He can even take a couple miles-per-hour off his fastball and still make hitters look foolish because even though 99 isn’t 101, it’s still pretty hard to catch up to.

A pitcher like Keuchel does not have such room for error. He can’t really afford to lose even a small tick off of his stuff. Unfortunately, that’s precisely what happened last year:

BrooksBaseball.net

It’s almost impossible to see here, but Keuchel’s four-seam and sinker overlap one another on this chart. There’s really two separate pitches there, and Keuchel throws the sinker much more often, but for our purposes, it doesn’t much matter. You can see the dropoff in velocity either way.

Now, just by looking at that chart you don’t need me to tell you that Keuchel wasn’t exactly bringing the heat before 2016. He was typically operating a little north of 90 MPH with that sinker.

In 2016, he lost a full mph off not just that pitch, but his slider and cutter as well. Keuchel did throw his changeup harder than ever, but that, of course, narrowed the velocity gap between his sinker and change — not always a good thing.

With that loss in velocity came harder contact from Keuchel’s opponents. Here’s a comparison of his exit velocities from 2015 and 2016, per Baseball Savant:

Baseball Savant

It’s pretty obvious from that GIF that hitters were not having nearly as much trouble doing damage when they made contact against Keuchel last season. In 2015, he was getting hit hard only when he threw the ball in the middle of the plate, which is, of course, not uncommon. In 2016? He was getting hit hard almost regardless of where he put the ball in the zone.

In fact, Keuchel finding the zone as often as he did may have been part of the problem. In 2013, the season before he took off, Keuchel stayed in the zone a little over 42 percent of the time, per FanGraphs data. In 2014 and 2015, he showed an improved ability to hit spots just outside the strike zone, ending those years with a zone percentage of 40 and 37 percent, respectively.

That may not seem like a big difference, but look at how Keuchel’s approach shifted over those three seasons, from BrooksBaseball:

BrooksBaseball.net

Primarily concentrate on those four boxes in the lower right. You can see a concerted effort to live in that area. Now, with that fresh in your mind, take a look at Keuchel’s 2016 zone profile:

BrooksBaseball.net

Speaking of zone percentage, guess what Keuchel’s was in 2016? 42 percent, when rounded — right about where it was before Keuchel went from back-end starter to Cy Young contender. So not only did Keuchel’s stuff regress, but his command did as well. The proof is right there in those charts.

As discussed earlier, pitchers in the Keuchel mold are walking a tightrope to begin with. It’s hard for them to get away with losing either their limited stuff or their superior command. Keuchel stepped back in both areas in 2016.

That doesn’t mean the 2016 version of Dallas Keuchel is a bad pitcher by any means. FanGraphs had him as a 2.7-win player; Baseball Prospectus gave him 3.5 WARP. That’s still an above-average pitcher. It’s just that, coming off a Cy Young, an above-average season feels like a disappointment.

For all the reasons for Keuchel’s down year that we’ve talked about throughout this article, we’ve hardly even mentioned that shoulder injury he was dealing with. An injury is never a good thing, but if Keuchel can get that right over the offseason, a clean bill of health could be a big reason to believe in some positive regression in 2017. It would certainly help to explain the loss of velocity and command on display last year.

Both Houston and Keuchel have to be looking forward to putting 2016 in the rear view, of course. Both parties are hoping that was a one-year blip caused by some nagging shoulder inflammation, rather than a sign that Keuchel’s window as a front-line starter was as short as we all feared.

Right now, projection systems such as ZiPS and Steamer are cautiously optimistic, projecting Keuchel for 3.5 and 4.1 WAR, respectively. That may not be the kind of superstar performance we saw in 2015, but that’s still a borderline All-Star, and Houston should and would be perfectly content with that.

The Astros have the hitting necessary to get to and win in October. They have the depth to persevere through injuries and a long regular season. Those aren’t questions marks. What is uncertain is whether they have a star to front their rotation, or will have to make do with a group of average to above-average starters. If Keuchel can once again perform like the former, this team may well be as good as we all think they can be.