Which pitchers are most likely to rebound in 2016? You could go with previously successful pitchers who missed most or all of last season and are working their way back -- guys like Yu Darvish, Hyun-Jin Ryu or Marcus Stroman. Or you could look to stars who seemingly had subpar year on the surface but were often still dominant, like Corey Kluber or Stephen Strasburg.
But the first group is too obvious, the second group too successful (and we've already singled out the reasons behind Justin Verlander's rebound). Instead, we'll use Statcast™ to look at two younger pitchers who may not have had the 2015 seasons they'd wanted, yet have plenty of reasons for optimism.
Rick Porcello, Red Sox
After being acquired for Yoenis Cespedes and then signed to an $82.5 million extension, Porcello had high expectations in his first year with Boston … which he promptly failed to meet, putting up his worst season since 2010. Of course, 2015 was a lost year for the Red Sox as a whole, and so it was easy not to notice when Porcello quietly began to turn it around later in the season.
Let's use Porcello's August stint on the disabled list as a dividing line -- though you really could push it back further, as he was good in three of his four starts immediately preceding his time off:
Pre-DL: 114.2 IP / 5.81 ERA / 4.71 FIP / 18.4 K percent
Post-DL: 57.1 IP / 3.14 ERA / 2.96 FIP / 24.3 K percent
Now, you know -- or should know -- that you can't simply look at the smaller amount of data and toss away the larger amount of data just because it doesn't suit the narrative. At no point are we pretending that Porcello didn't struggle for most of the season. However, working in our favor is the fact that Porcello made a real tangible change to the way he pitched -- he went back to pitching like the old version of Porcello.
Gif: Rick Porcello strikeout reel
Let's explain. In every year of his career, Porcello has used his sinker more than anything else, throwing it nearly 60 percent of the time as a rookie in 2009. But during his struggles in 2015, he was using his four-seam fastball more than ever, at the expense of the sinker:
Pre-DL: 30.7-percent four-seam / 34.3-percent sinker
Post-DL: 18.4-percent four-seam / 49.0-percent sinker
With an above-average spin rate of 2,477 rpm on his four-seamer, it wasn't necessarily a bad plan for Porcello to attempt to throw it high, keep the sinker low and move the hitter's eye level. The problem was that he was unable to locate it well enough, leading to hittable four-seamers in the zone that would get crushed. As you can see, Porcello left far more of them in the zone before than after:
Pre-DL: 45.5 percent of four-seamers in strike zone
Post-DL: 36.6 percent of four-seamers in strike zone
Now apply that percentage to the fact that Porcello was throwing nearly twice as many four-seamers before the DL, and you can see the issue. Add in the fact that there's evidence he's added more bite and separation to his curve and there's plenty to like about a pitcher who is just 27 years old.
Alex Wood, Dodgers
Wood came to Los Angeles last July in a massive deal that so far hasn't looked great for anyone (neither Mat Latos nor Jim Johnson lasted through the season as Dodgers; for Atlanta, Hector Olivera has already been moved off of third base and Paco Rodriguezblew out his elbow). The once-touted Wood struggled in 12 starts, putting up a 4.35 ERA (4.10 FIP) and seeing his strikeout frequency plummet.
But it turned out there might have been a few reasons for that. Wood's notoriously funky mechanics had deteriorated to the point that his vertical release point was nearly a half-foot lower than it had been during his successful 2013 and '14 seasons:

Dodgers pitching coach Rick Honeycutt reportedly had some ideas about how to fix those mechanics, but as Wood told a local paper last week, a bruised right ankle suffered in his final start for Atlanta impacted him to the point that he "was basically trying to find a way to not crush my foot every time I landed on it," making it impossible to implement the changes.
Now, Wood's ankle has healed after a offseason of rest, and regular mechanics video work has allowed him to say that his "arm is way higher … a lot of major differences for sure."
Gif: Wood K 2
This is veering dangerously into "best shape of his life" territory, of course, but consider what we know. Wood turned 25 in January, and as his velocity dropped from 92.5 mph to 89.8 mph between 2014 and '15, the vertical movement on his curve dropped from six inches to a mere 1 1/2 inches over the same span. We don't know his spin rate from previous years, but we do know that none of his pitches topped 2,000 rpm in 2015.
That's not the pitcher we saw with Atlanta. It's not hard at all to believe that Wood's mechanical issues played something of a role there, and the foot injury exacerbated it further. With Ryu out until May, he'll get a chance to prove it.