Since the Supreme Court decided the case in 1938, Erie Railroad Co. v. Tompkins has limited the application of the Federal Rules of Civil Procedure. By changing shape, Erie has eluded the Court’s attempts to curb its influence for most of the past century. Only recently, in Shady Grove Orthopedic Associates, P.A. v. Allstate Insurance Co., did the Court manage to apply a Federal Rule over Erie‘s contrary command to apply state law, but that decision so divided the Court that no one opinion enjoyed the support of five Justices. The resulting confusion among the lower courts over which should serve as Shady Grove‘s holding has allowed Erie to escape again in a new form. This Note argues that these courts have overlooked Justice Sotomayor’s hidden “opinion,” which decided Shady Grove on the narrowest grounds and would have avoided their conflicting decisions.