For the second straight year, Gonzalez's numbers took a step backwards. His ERA was a full run higher than it was just two years ago, and his 90.8 mph average fastball is disconcerting for a pitcher who has sat at 92 mph or better for most of his career. Nonetheless, he won at least 10 games and struck out at least 160 batters for the seventh straight season, and that consistency made it a no-brainer for the Nationals to pick up the $12 million option on his contract for 2017. In a rotation dominated by power righties, Gonzalez's big curveball from the left side gives opposing hitters a very different look, and while he probably won't approach the 21 wins he amassed in 2012 again, he should help solidify the back end of the Nats staff -- assuming that his lost fastball velocity isn't a sign of a further decline ahead.

In many ways, 2015 was the worst season of Gonzalez's career. His 1.42 WHIP was his highest since he became a full-time major leaguer in Oakland, and he struggled to put away hitters and keep his ERA below 4.00 in the first half. Things returned to something closer to normalcy for Gio after the All-Star break, as a 7.9 K/9 rate in the first half gave way to a 9.6 second-half K/9 and nearly a half-a-run drop in his ERA. The 30-year-old left-hander still works off a low-90s fastball and vicious curveball, and his WHIP spike is tied to a big increase in his groundball rate and BABIP. More grounders is usually a good thing for a pitcher, so if those rates normalize, he simply gets more support behind him or has better luck on those grounders, it wouldn't be a shock to see Gonzalez rebound to post numbers closer to his career 2012 season.

For the first time in his major league career, Gonzalez dealt with a serious injury, as shoulder inflammation limited him to just 158.2 innings. His 10 wins were his lowest total since he became a rotation regular in 2010, but aside from the restricted workload, his overall stats were very similar to the year before and his K/9 rate ticked back above 9.0. As a result of the arm trouble, he relied on his premier curveball less than he had in previous seasons, throwing it a career-low 17 percent of the time, but Gonzalez compensated with increased usage of an effective changeup to keep batters off his low-90s fastball. Assuming the shoulder problems weren't a sign of bigger issues to come, he should be able to return to his usual level of production, and renewed confidence in his changeup could even be a boon in the long run. Just don't expect another 20-plus win, sub-3.00 ERA repeat of 2012 from Gonzalez.

Gonzalez couldn't duplicate his Cy Young-worthy 2012, as his BABIP, K/9 and HR/9 all returned to the level he'd established during his Oakland stint. Cynics will sneer at his vague association with the Biogenesis furor as the reason for the regression, but you don't need wonder drugs to have a big season. Gonzalez's curveball is still a work of art, and he's been very healthy throughout his career. Consider last year's numbers a relatively safe baseline as pitchers go, and if the Nationals remember how to score some runs for him, his wins and overall value should tick up.

Some improvement was expected from Gonzalez with his move away from the DH league, but no one saw an ascension quite this dramatic coming. Focusing more on getting ahead of hitters with his fastball made his vicious curve that much more effective, and his 2.7 K/BB ratio was by far a career best. He will likely see some regression in a lucky 5.8 percent HR/FB rate, so an ERA that creeps back above 3.00 would not be a surprise, but if he can continue to refine his control and stay in games longer his overall fantasy value could actually increase. Despite seeming like he has been around forever Gonzalez is still only 27, and the best might be yet to come.

Gonzalez followed up his 2010 breakout with a nearly identical 2011 season, adding nearly 30 strikeouts to his already impressive strikeout rate. He still walks too many, issuing another 91 free passes in 202 innings, and he faded a bit as the season progressed (3.94 ERA, 1.371 WHIP after the All-Star break, though the peripherals remained strong). Gonzalez was traded to the Nationals in the offseason for a package of prospects and should be Washington's No. 2 or No. 3 starter. He's done a better job of getting more groundouts, but landing in a hitter's park with a poor outfield defense could hurt him more than most.

Gonzalez finally had the season many had envisioned, posting 15 wins and fanning 171. The long ball, a long-time nemesis of Gonzalez when combined with his poor control, was largely eliminated in 2010 as he allowed just 15 home runs in 33 starts. He still walks too many, but got away with it by allowing just 171 hits in 200.2 innings this year thanks to a .283 BABIP figure (a drop from the .369 mark the year prior). There are still plenty of warning signs going forward, as his strong August (0.927 WHIP, 1.98 ERA) sat amongst a string of month-by-month WHIPs of 1.472, 1.584 and 1.545 His home ERA (2.56) was a marked improvement from his road figure (3.92). He hasn't turned the corner from prospect to legit starter just yet, and his season was remarkably similar to that of C.J Wilson. The odds of both repeating their 2010 seasons given their poor control are pretty low, though the A's outfield defense gives Gonzalez's flyball tendencies some wiggle room.

Gonzalez shuttled back and forth from Triple-A Sacramento to Oakland early in the season before getting a prolonged look in the A's rotation as the season progressed. His control was shaky at Triple-A (34 walks in 61 innings), but his other numbers (41 hits, 71 K) showed promise. He continued to show upside (81 K over his final 74.1 innings in the majors) and show warts (42 walks and a 1.614 WHIP over the same period) once he reached the majors for good. Unfortunately for Gonzalez, control problems have long been an issue for him and he doesn't show any sign of turning that particular corner. His effectiveness will be limited as a starter until he's able to solve that problem, and his future may come in a relief role as a result. Still, his strikeout potential makes him a better endgame gamble than most.

Acquired in January from the White Sox, Gonzalez struggled with his control at Triple-A Sacramento before a seven-start audition with the A's proved similar. He'll get a prolonged look in the A's rotation in 2009, but he wouldn't be the first pitcher to have his development halted by the inability to throw consistent strikes. The strikeout potential separates him from other endgame options though, so don't dismiss him entirely.

Gonzalez led the Southern League with 185 strikeouts as a 21-year old. The left-hander offers an outstanding curve, a fastball with movement and an improving changeup. He'll need to get some minor control issues ironed out but he showed improvement in that area this season. He limited Double-A hitters to a .230/.305/.336 line away from the pitching-friendly environment in Birmingham so he wasn't a product of his home environment. He instantly becomes one of the top prospects for the A's, following his trade to Oakland as part of the package for Nick Swisher in January. At the very worst he'll start the season at Triple-A and figures to get a look at the big leagues at some point this season.

Gonzalez pitched pretty well at Double-A, especially when one considers the 20-year-old was just in his second full pro season. The lefthander has a low-90s fastball and a good curveball, although his command is erratic (166:81 K:BB). The White Sox, who originally signed him in 2004, re-acquired him in December in the Freddy Garcia deal. Gonzalez needs to control his emotions better -- scouts have noted he tends to throw instead of pitch when under pressure -- but a strong season could see him in the majors in September.

Just as Brandon McCarthy threatened to leave prospectdom behind and join the major league roster, Gonzalez -- a second round pick lured away from a University of Miami scholarship in 2003 -- stepped into the vacuum and assumed the mantle of top pitching prospect in the organization. His time as king of the hill was short-lived, although thankfully not due to the usual arm woes -- he'll get his first crack at the high minors as property of the Phillies.