The Rays' right-hander finished 2010 with a 5.18 ERA, the fourth-highest ERA in the Majors, due in part to mechanical issues, some bad luck on balls in play and an unusually high number of fly balls landing over fences. In the postseason, there was talk of leaving him off the playoff roster.
But Shields completely turned it around this past season, becoming one of the best starting pitchers in the American League. He threw a Major League-leading 11 complete games, tossed four shutouts and posted a 2.82 ERA in 249 1/3 innings while winning 16 games -- all career bests.
With that kind of dramatic turnaround in mind, which pitchers might be poised for a bounceback year after a rough 2011? Who is poised for a breakout season? Here are a few pitchers to keep an eye on:
Ubaldo Jimenez, Indians: Was 2011 a fluke or a sign of things to come for Jimenez? The righty posted a 4.68 ERA in 2011, showing signs of decreased velocity while giving up a career-high 17 homers and struggling to strand runners when he put them on base. Jimenez unexpectedly faltered only a year after an All-Star season in which he finished third in the National League Cy Young voting while pitching for Colorado. Even if he doesn't return to his 2010 form, Jimenez -- dealt to Cleveland in July -- figures to at least rebound from a down season.
Fausto Carmona and Derek Lowe, Indians: Carmona (5.25) and Lowe (5.05 with the Braves) recorded two of the five worst ERAs in the Majors in 2011. Both are ground-ball pitchers, so their fates could be tied to the performance of their respective infield defenses. Carmona followed a terrible 2009 (5-12, 6.32 ERA) by going 13-14 with a 3.77 ERA in 2010, and he will look to right the ship further in '12.
Ryan Dempster, Cubs: Dempster had a breakout season in 2008 (17-6, 2.96 ERA) and posted a 3.65 ERA in '09 and 3.85 ERA in '10 before hitting a snag this past season. He wasn't able to make hitters swing and miss as often as he did in previous years, but the veteran righty should still improve next year on his 4.80 ERA from this season.
Ricky Nolasco, Marlins: Nolasco's numbers don't exactly jump off the page, but a deeper look into his peripheral statistics reveals the potential for a turnaround. He went 10-12 with a 4.67 ERA in 2011, but he threw 206 innings with a Fielding Independent Pitching (FIP) figure of 3.54. With improved defense behind him and a few breaks going his way, Nolasco's line could look more like it did in 2008: 15-8, 3.52 ERA and a 1.10 WHIP in 212 1/3 innings.
Jonathan Sanchez, Royals: Sanchez has been plagued by walks and inconsistency, and he can be frustrating for fans to watch at times. But he has shown the ability to frustrate hitters, too. The lefty battled fatigue and injuries a year after the Giants' World Series run, so a change of scenery could help him get back on track. Keep in mind, he isn't far removed from a stellar 2010 season in which he recorded a 3.07 ERA and dominated opponents down the stretch.
Brandon Morrow, Blue Jays: Morrow seems like a lock to once again lead the AL in strikeouts per nine innings, but could 2012 be the year when he puts it all together? The hard-throwing righty pitched to a 4.72 ERA in 2011 while racking up 203 strikeouts in 179 1/3 innings. Morrow walked 3.46 batters per nine innings and induced only one double play all season, two things that hurt his chances of stranding runners and drove up his ERA. If that changes, Morrow could be on the verge of a big year.
Madison Bumgarner, Giants, and Brandon McCarthy, A's: Neither pitcher needs to bounce back, but they could be ready to take a next step forward. Both flew under the national radar despite successful seasons, partially because their traditional numbers don't stand up with the best in the game.
Bumgarner finished the year with a 13-13 record and 3.21 ERA, and McCarthy went 9-9 with a 3.32 ERA. But their strikeout-to-walk ratios and ability to minimize home runs made them two of the Majors' best in FIP, a performance-based metric that also serves to predict future success, and make them prime breakout candidates in 2012.
Bumgarner (2.67) and McCarthy (2.86) finished behind only Roy Halladay, Clayton Kershaw and Cliff Lee in FIP last season. Will Bumgarner and McCarthy be mentioned alongside those Cy Young-caliber aces next year? That's impossible to predict. But if 2011 was any indication, both Bay Area pitchers could be on track to quickly work their way into the spotlight.
Adam Berry is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.