George Jasper Caster (August 4, 1907 – December 18, 1955), nicknamed "Ug", was a right-handed professional baseball pitcher for 21 years from 1929 to 1948 and again in 1953.

He played 12 years in Major League Baseball with the Philadelphia Athletics (1934–1935, 1937–1940), St. Louis Browns (1941–1945), and Detroit Tigers (1945–1946).

[2] Caster played shortstop until his senior year, when injuries to Colton's pitchers led to his taking up pitching.

[3] After compiling a 12–5 record in 20 games with San Bernardino, Caster was promoted to the Pacific Coast League, playing for the Mission Reds from 1929 to 1932.

He divided the 1934 season between Seattle and the Portland Beavers of the Pacific Coast League, compiling a 1–15 record and 3.40 ERA in 34 games.

[9] In a front page profile, The Sporting News credited Caster's turnaround to overcoming his lack of control and adding a slow knuckleball to his blazing fastball and sharp-breaking curve.

"[11] United Press writer Paul Scheffels described Caster's approach this way: "This 6-foot-1-inch righthander from California has a delivery as simple as a fat woman's diet.

[11] In 1939, he pitched on opening day for the Athletics against the Washington Senators in Washington, D.C. President Franklin Roosevelt attended the game, in which Caster pitched a shutout; Caster later described the opening day shutout in front of the President as one of the greatest thrills of his baseball career.

In 1941, Luke Sewell converted Caster into a relief pitcher, and he had the best seasons of his major league career as the Browns' lead reliever from 1942 to 1944.

[12] The 1945 Tigers went on to win the American League pennant and defeated the Chicago Cubs in the 1945 World Series.

Caster appeared in a total of 22 games for the 1945 Tigers, all in relief, compiling a 5–1 record and 3.86 ERA in 511⁄3 innings.

[7][16] He attempted a comeback five years later, serving as a player-coach and appearing in eight games for the Edmonton Eskimos of the Western International League in 1953.

[1] He suffered a heart attack while attending a Christmas party hosted by his employer Douglas Aircraft Company.