Last season, A.J. Burnett pitched 191 stellar innings, leading Pittsburgh to its first postseason appearance since Sid Bream’s slide ended the 1992 NLDS. Burnett’s 3.30 ERA was backed up by even better peripherals, as his 2.80 Fielding Independent Pitching (FIP) mark was fifth among qualified NL hurlers. While Burnett certainly deserves a lot of credit for his own excellence, the Pirates’ front office put him in a position to succeed, deploying a stingy and well-aligned defense behind him. Although Burnett didn’t always agree with the alignment of that defense, he certainly benefitted from it. As one of the most extreme groundball pitchers in the game, Burnett gets disproportionate benefits from a strong and well-positioned defensive infield like the one he pitched in front of last year, while a poor group of infielders could hurt him more than most.

Unfortunately for Burnett, his new coworkers include just such a group of infielders. While Pittsburgh received solid infield defense across the board last season, the Phillies occupied the other end of the spectrum, combining around the horn to allow 50 runs more than an average group of infielders. While 18 of those runs are attributable to the now-retired Michael Young, Young’s replacement is unlikely to be stellar, either. Cody Asche, who cost the team seven runs in nearly 400 late-season innings in 2013, is projected for -10 DRS this season, so we’ll replace Philadelphia’s atrocious 25 runs cost at the hot corner in 2013 with that more generous -10.

Defensive Runs Saved by Position, 2013


































In order to provide a rough estimate of what AJ Burnett’s 2013 would look like with the 2014 Phillies, we’ll assume that those runs cost and saved were evenly distributed. That is, given that Burnett’s 191 frames accounted for 13 percent of the innings tossed by Pirates pitchers last year, we’ll assume he benefitted from 13 percent of the runs saved by their defense. While a more in-depth analysis would consider Burnett’s batted ball types, pull percentages, and the resulting impact of the various fielders on his performance, for simplicity’s sake, we’ll stick to the quality of the defense behind him as a whole to estimate the magnitude of the possible effect on Burnett’s numbers.

This back-of-the-envelope calculation estimates the Pirates’ defense saved Burnett just over nine runs last season. Replacing Philly’s third base defense with Asche’s projection (a 15-run improvement) and assuming Burnett shoulders a similar percentage of the pitching load for the Phillies this year results in an estimated 11 additional runs cost against an average defense by the gloves behind him. Burnett allowed 79 runs last season, so by this admittedly simple accounting, the switch in defenses would bump that up to a little over 99 runs.

Burnett will also be switching parks from a fairly pitcher-friendly PNC to the homer-happy Citizen’s Bank. Making the broad assumption that his talent level at home and on the road is fairly similar, we’ll bump his runs at home up from 49 (half of the defense-adjusted 99 runs) by about 22 percent, or the difference between Pittsburgh and Philly’s park factors for runs. Between the less favorable defense and park, we’d now expect Burnett to allow 109 runs next season, raising his runs allowed per nine innings from 3.72 to 5.13.

In other words, by this estimate, the change in defenses and parks drops Burnett from a pitcher in the top half of the league to nearly the same level of production as the 2013 season of his new rotation-mate, Kyle Kendrick. While Burnett may have complained about the Pirates’ atypical alignments last season, it probably won’t be long before he’s pining for his days in western Pennsylvania.