NL Central 2014: Starlin Castro, Wily Peralta most likely to improve

Starlin Castro - An obvious candidate because... what other direction is there to go? Castro hit an abysmal .245/.284/.347 last year, "besting" his career low OPS by over 120 points, while setting a career high in strikeouts. Add in Castro's history of success, and it seems a reasonable gamble that he can return to form -- at least in part. Castro suffered from poor luck on balls in play, posting a .290 BABIP, and before we get to his increased strikeout percentage and declining line drive rate, he increased his groundball rate which should offset at least some of those losses. he's got a career .323 BABIP, which would suggest that his .290 BABIP was low. His batted ball stats in 2013 are eerily similar to those in his debut season (2010), so it's not as though he's never been successful with this kind of approach. A change in luck won't fix everything, but a return to a more aggressive approach may actually help, as patience at the plate the Cubs were preaching didn't seem to sit well with him.

Devin Mesoraco - The Reds' trade of Ryan Hanigan sets Mesoraco up for the every day catching duties, something previous manager Dusty Baker seemed reluctant to do. Still, he did receive almost double the at-bats from the year before, with only marginal improvements to show for it -- not exactly earning the starting role. Mesoraco has prospect pedigree, and while that has to stop counting at some point, we're barely over a season's worth of at-bats into his career. He has shown the ability to overcome failure before (check his numbers from his first three minor league seasons), and he's suffered from a bit of bad luck in his brief major league tenure. Again, BABIP isn't a panacea that always returns to the major league average -- especially since Mesoraco's career number rests at .248 -- but he's shown a groundball-heavy batting profile throughout his career, and upped his line drive rate to 21% last year. Those types of numbers don't typically result in a .264 BABIP (2013 number), allowing to expect some movement toward the league average if Mesoraco can produce the same types of swings.

Wily Peralta - A rough first gave way to a stronger finish for Peralta, who had shown promise in a short stint in 2012. While he may not have been a decorated prospect, most thought Peralta had the stuff and frame to log in the back end of a rotation, if not the middle. While a return to health from Aramis Ramiez will actually hurt Peralta a bit, the extreme groundballer has an intriguing mix of skills. He has a career 51.5% ground ball rate in the majors, and while he's struggled to miss bats in that time, he has a history of doing so in the minor leagues. His early season struggles brought about a steep learning curve, but once he learned to rely on his slider, he began to miss bats - recording a 3.48 ERA from June on. The slider plays well off of Peralta's impressive fastball, and with the Brewers' acquisition of Matt Garza, there's less of a conceptual load for him to carry. An ERA in the mid-threes seems eminently attainable for the young hurler.

Neil Walker - More than anything, "most improved" for Walker would be a return to normal. Walker's career line sits at .273/.339/.418, while his 2013 line was .251/.339/.418. At 27, it's not as if Walker suddenly hit his decline phase, either. BABIP once again rears it's ugly head, as Walker's was .274 in 2013 compared to his career average .312. He did see a dip in his groundball rate (about four percentage points), but his line drive rate stayed relatively steady at an impressive 23%. Even with those declines though, nothing suggests the severe decline in batting average that Walker suffered through. He did compensate by walking more frequently, and if he can combine a return to a standard BABIP with this increased walk rate, Walker and the Pirates' might in line for a career season.

Lance Lynn - Let's start with the obvious, in that Lynn's FIP sat seven-tenths of a run lower than his ERA, indicating that we're in for something of a bounce-back. Add in that the rest of the Cardinals were pretty darn good, and there just weren't that many options available on a loaded team. Still, the best reason for improvement would be if Lynn pitches out of the bullpen -- a distinct option with the return of Jaime Garcia and the emergence of Joe Kelly -- remember Lynn was bumped to the pen in favor of Kelly in the playoffs. With a starter's repertoire, Kelly presents problems for hitters that other relievers don't pose, in addition to the bump in velocity he could get by airing it out instead of conserving energy over extended innings.