Prior to the 2013 season kick off for the Phillies, much of the talk surrounded the bullpen, and how the group of young relievers was aligning to be a strength for the club. It was supposed to be a turnaround season for the relief corp, who only a year earlier struggled, despite the addition of closer Jonathan Papelbon.
As it turns out, the bullpen was one of the low points for the 2013 Phillies, as they allowed more runs per game than all but one National League team. It was a frustrating spectacle, to say the least, and it was chief among the reasons the Phillies finished well under .500 for the first time in a decade.
The 'pen was not without it's bright spots, however, as anyone who watched Jake Diekman this year can attest. After a decent rookie season in 2012 where the lefty demonstrated an ability to strikeout hitters as much as walk them, he took a huge step forward in 2013 and emerged as a dominant Southpaw in the bullpen alongside Antonio Bastardo.
In 38.1 innings of work (a reduced Major League workload due to starting the season with Lehigh Valley), Diekman had a 2.58 ERA with 9.6 strikeouts per nine innings, as well as much improved BB/9 of 3.8 (down from 6.6 in the previous season). As a reliever, the ability to limit the walks is a crucial one, and Diekman did so by spotting his fastball, which allowed him to turn his slider into a dominating out-pitch.
Diekman has been particularly effective against left-handed hitters, whom he held to a .368 OPS in 61 at-bats this season. 23 of those at bats resulted in strikeouts, while only six of them resulted in walks. He wasn't as successful against right-handed hitters (they got on base against him at a .372 pace), which is why Diekman's lot in life may very well be as a left-handed specialist who only occasionally faces righties.
The thing about Diekman is that he is all of 26-years-old, so he figures to only get better over the next few years if he can continue to keep his control in check. As I see it, the greater responsibility lies in Ryne Sandberg's management, and how he decides to use his pitcher. If he is used exclusively against lefties, then he very well may be one of the most effective relievers in the game in 2014.