Definition of pinch runner in US English:

pinch runner

noun

Baseball
  • A player who substitutes for a teammate as a base runner, typically at a critical point in the game.

    ‘he came in as a pinch runner after Turner strained his left hamstring’
    • ‘Adjustments like pinch runners or last-minute changes in batting order are allowed to help keep injury rates low.’
    • ‘Five of those six appearances were as a pinch-runner and one as a defensive replacement.’
    • ‘Him and Davis need to be used primarily as pinch runners.’
    • ‘His pinch-runner doesn't score, and the Yanks lose the game and the series.’
    • ‘His meager bat means he will probably just be a pinch runner in 2014.’
    • ‘However, later events suggest that even a pinch runner would have had some value.’