In the 9th inning at Ebbets Field, pinch-hitter Clarence Mitchell, batting for starter Leon Cadore, hits a two-run homer, but the Dodgers come up short, losing to Boston, 5 – 4. Mitchell’s blast is the first pinch homer by a Dodgers pitcher.

On May 29, 1922 — In the 9th inning at Ebbets Field, pinch-hitter Clarence Mitchell, batting for starter Leon Cadore, hits a two-run homer, but the Dodgers come up short, losing to Boston, 5 – 4. Mitchell’s blast is the first pinch homer by a Dodgers pitcher.

Source:
Baseball Reference May 29