1921 – In his first at bat‚ St. Louis Browns rookie Luke Stuart hits a home run‚ becoming the first American League rookie to accomplish the feat. His 9th-inning blast‚ good for 2 runs‚ comes off no less than Washington’s Walter Johnson. Johnson‚ leading 16 – 3 after his teammates score 7 runs in the 8th‚ cruises home with a 16 – 5 win. Stuart‚ who appeared in one game on July 28th but did not bat‚ will play one more game and then leave the majors with this home run as his only hit. The next AL rookie to connect for a homer on his first at-bat will be Earl Averill in 1929.

On August 8, 1921 — 1921 – In his first at bat‚ St. Louis Browns rookie Luke Stuart hits a home run‚ becoming the first American League rookie to accomplish the feat. His 9th-inning blast‚ good for 2 runs‚ comes off no less than Washington’s Walter Johnson. Johnson‚ leading 16 – 3 after his teammates score 7 runs in the 8th‚ cruises home with a 16 – 5 win. Stuart‚ who appeared in one game on July 28th but did not bat‚ will play one more game and then leave the majors with this home run as his only hit. The next AL rookie to connect for a homer on his first at-bat will be Earl Averill in 1929.

Source:
Baseball Reference August 8
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game