Pinch Runner (1908)

“G. [George] Winter made his usual appearance as pinch runner after Schmidt singled in the eleventh.” The Detroit Times, September 12, 1908. p3

Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1ST USE. 1911. “Pinch Runner Nipped by Hidden Ball Play, Breaking up Late Rally” (Chicago Daily Tribune subheadline, Sept. 2).