Or, how to magically create better pitchers without changing any of your pitchers...
This is a link to the highlights of last night's 8-2 Braves win over the Marlins. The sixth video in the sequence is titled "Simmons turns two."
From Opening Day until his demotion last week, former Braves SS Tyler Pastornicky accrued an abysmal -11 bRAR (runs above/below replacement, via Baseball-Reference.com.) Since that demotion, and the call-up of Andrelton Simmons that went with it, Simmons has already accrued a bRAR of 3.
This is another link, this time to FanGraphs.com's stats reports for Braves pitching, sorted by ground ball percentages.
Simmons has been touted as a defensive wizard since becoming a full time position player. His performance to date is in line with expectations and scouting reports. (His early bat has been an unexpected plus.) In the next few months, expect the guys at the top of that list to benefit significantly from going from a terrible defensive SS to a true defensive asset in that hole. Note that in addition to infamous sinker-baller Tim Hudson, all three of the shut-down relievers in the pen - Kimbrel, Venters and O'Flaherty - induce grounders when they're not striking batters out.
Note also that the other two pitchers who induce ground balls at a 50/50 clip or higher are Randall Delgado and Kris Medlen (currently stretching out as a starter in AAA.) Compare to the last guy on the list, Mike Minor, who is decidedly not a ground ball pitcher. In the battle for the final rotation spot, Delgado and Minor are "pitching for the slot," and in addition to simply out performing Minor to date, Delgado should benefit dramatically from having Simmons making plays behind him on the infield, while Minor will continue to rely on his outfielders to chase down fly balls when they can.
Welcome back to Gwinnett, Mike.