Corbin took a big step forward in 2017, but few could have predicted his ascension to full-fledged ace-dom in 2018. The lefty's strikeout rate exploded, leaping from 21.6% to 30.8%. His slider graded out as the best slider among qualified starters per FanGraphs, and thanks largely to that dominant pitch he led qualifiers in O-Swing%. Corbin's fastball and curveball were plus offerings, and with Corbin nearly halving his home-run rate, the estimators put him in the same class as Max Scherzer and Aaron Nola among the best options in the National League. The numbers only got stronger as the season wore on, making Corbin the most coveted arm on the free-agent market this winter. The Nationals won the sweepstakes and should insert Corbin behind Scherzer atop the rotation to start the year. While he doesn't have the track record of success that many other top-end arms do, Corbin's skills are legitimate and worth paying a premium for.

Corbin rescued his 2017 season by posting a 3.26 ERA after the All-Star break, ranking 15th among starting pitchers, and matched his career-best 14 wins. The southpaw rediscovered dominance at 8.5 K/9, thanks to boosts in first-pitch strikes (62.5 percent), swinging strikes (11.0) and pitches in the zone (43.1). That looks good when paired with his elite groundball rate (53.8 percent in 2016, 50.4 in 2017). The young vet thrived with Jeff Mathis behind the plate (3.41 ERA in six starts) and could approach his 3.15 home ERA again with the Diamondbacks installing a humidor at Chase Field. However, his outlook would be sunnier had he not lost control the last two years (3.3 BB/9 combined), and he must figure out how to tame righties, who tagged him for a .349 wOBA last season. The 28-year-old also leans heavily on his slider, a common cause for health issues. That said, he looks to have returned to pre-Tommy John form and can be had at a low cost in many drafts.

In his first full season back after 2014 Tommy John surgery, Corbin fell well short of expectations. He was a bit up and down out of the gate but had a 3.99 ERA on May 20 after posting a quality start against St. Louis. From that point on, however, the lefty posted a 5.80 ERA and 1.70 WHIP. In August, the team decided to move Corbin to a relief role, and he actually did pretty well. As a reliever, Corbin posted a 2.70 ERA and 26 strikeouts over 23.1 innings. Of course, Corbin holds more long-term value if he can be an effective starter again, and given Arizona's struggles in the rotation last season, he could snag a spot in 2017. Remember, this is a guy who posted a 3.41 ERA, 1.17 WHIP and 178 strikeouts over 208.1 innings in 2013, before the surgery. If Corbin finds a way to approach those kinds of numbers again, he'll be a useful fantasy option. At the very least, he'll likely come at a steep discount in drafts.

After undergoing Tommy John surgery during spring training in 2014, Corbin missed all of the 2014 season and a big chunk of the 2015 season. He returned to the rotation July 4 and went 6-5 with a 3.60 ERA the rest of the way, striking out 78 batters in 85 innings. In 2016, the Diamondbacks expect to get a full season out of Corbin, although they may exhibit some caution with his innings total. Corbin’s last full season was in 2013, when he made the NL All-Star team. That year, Corbin went 14-8 with a 3.41 ERA across 208.1 innings, while racking up 178 strikeouts. He won’t reach that innings total this year, but he could be a solid fantasy contributor who posts useful ratios plus a decent number of wins and strikeouts.

Corbin never had a chance to show how real his stud effort from 2013 was as he went down with Tommy John surgery in late March. The last time we saw him he was cutting up the league for 208 strong innings with very useful ratios and a decent strikeout rate. The breakdown of that season left some questions about how much to trust it, though. He had a 2.24 ERA through his first 21 starts before posting a 6.05 ERA in his last 11. He allowed 10 home runs during that run, highlighting the biggest concern with Corbin. He had a 1.2 HR/9 rate in 2012, but then allowed just 0.6 HR/9 in those 21 starts through July 2013. The equation seems simple: keep the ball in the yard and enjoy the success that comes with it, but executing that equation is the difficult part for any pitcher. The Diamondbacks are targeting a June return for Corbin, though expectations on the fantasy landscape should be kept to a minimum. He could play himself into a streaming option for spells during 2015.

Before the All-Star break, Corbin was having a potential Cy Young year, posting a 2.35 ERA in the first half, but his less-than-stellar second half (5.19 ERA, .286 BAA) sunk his overall season stats. Still, he was a pleasant surprise for those who took a late flyer on him, thanks in large part to his ability to pound the strike zone and maintain steady peripherals with an uptick in fastball velocity (he averaged a career-high 92.1 mph). It remains to be seen if he can be a true ace, but he still figures to be at the top of the Diamondbacks' 2014 rotation.

After pitching very well during his first exposure at Triple-A Reno, Corbin entered the mix for the Arizona rotation and held his own despite seemingly poor results. Although his strikeout rate fell in the big leagues (7.2 K/9) from Reno (9.5 K/9), Corbin demonstrated good control (2.1 BB/9) and his primary weakness was a propensity to give up home runs. Things appeared to click for Corbin in August, as he had a 34:8 K:BB in 36.2 innings (3.68 ERA, 1.15 WHIP) before struggling in September. A former second-round pick, Corbin is often overlooked as the second piece of the trade that once sent Dan Haren to Anaheim, but he's a polished left-hander with good control of a four-pitch arsenal, and should be a frontrunner to land a rotation spot in spring training.

Corbin is often overlooked as the "other" prospect the D-Backs received in the Dan Haren trade with the Angels in 2010, but he's proven to be a nice young pitcher in his own right. The 22-year-old led the Southern League in innings pitched (160.1) and strikeouts (142) while pushing his way into consideration for a late-season callup to Arizona. Thanks to a stockpile of young pitching talent, Corbin will likely spend most of 2012 at Triple-A Reno and could ultimately be a trade chip if the likes of Tyler Skaggs and Trevor Bauer make their respective big league impacts as expected.

Corbin was one of the farmhands included in the Dan Haren trade orchestrated by interim general manager Jerry Dipoto in July. While he wasn't the centerpiece, the development of Corbin and Tyler Skaggs will ultimately determine whether the D-Backs received an acceptable return for their ace. At age 21, Corbin finished the season strong at High-A Visalia and compiled a 136:37 K:BB over 144.2 innings between Low-A and his two High-A clubs. While Corbin may not have the arsenal of a future ace, he still has projectability if his velocity increases and he could advance quickly depending on how his first taste of Double-A goes.