As someone who adored the blog Fire Joe Morgan, this ad is fantastic.
For anyone unfamiliar with FJM, it's a blog that turned the baseball world on its head from 2005-2008. The authors, who just so happened to write for The Office full-time, hysterically lambasted established baseball analysts. They pushed for the use of advanced statistics to measure players and abhorred the old school standards of batting average, RBIs and "playing the game the right way."
The lead author, Michael Schur, is now the show runner for Parks and Recreation and recently had this subtle shoutout to his old blog. The above sign is for the law offices of Babip (Batting Average on Balls in Play), Pecota (Player Empirical Comparison and Optimization Test Algorithm), Vorp (Value Over Replacement Player) and Eckstein (Second Baseman David Eckstein). The blog often excoriated announcers love for Eckstein, who was seen as an exemplar of hustle and grit. Meanwhile, FJM used advanced stats to prove he was essentially a below-average player. Well, Eckstein caught wind of the dig and responded with an ad for his (fictional) firm. It's perfect.