Early career and New York Giants In 1929, Rosenberg played for in the
California Winter League. Rosenberg signed with the
Double-A Mission Reds of the
Pacific Coast League (PCL) in 1930.
The Deming Headlight described Rosenberg's play in the PCL as "the quickest rise to fame of any player in the Pacific Coast League in years". Mission also received two players from the Giants as compensation. Rosenberg held-out when the Giants called for him to report because he claimed the team owed him a US$5,000 bonus. The Giants eventually played him and he reported. In that game, he made two
plate appearances, getting one
walk. The reason for the salary increase, it was announced, was due to Rosenberg's appeal to the
Jewish community in New York City. However, he spent the entire season in the minor leagues. With the
Class-A Bridgeport Bears of the
Eastern League, he batted .329 with 91 hits, 17 doubles, nine triples, and two home runs in 71 games played. From there, Rosenberg was promoted to the Double-A
Newark Bears of the
International League, where he batted .284 with 19 hits, three doubles, and one triple in 21 games played. The Giants also farmed Rosenberg to the Double-A
Indianapolis Indians of the
American Association. With the Indians, he batted .330 with 37 hits, 10 doubles, and one triple in 35 games played. Between the three teams, he made 12
errors in the outfield.
Indianapolis Indians After the 1931 season, the Giants traded Rosenberg, along with
Jack Berly,
Johnny Cooney, and
Joe Heving to the Double-A Indianapolis Indians in exchange for
Len Koenecke. Rosenberg spent the entire 1932 season with the Indians. He batted .318 with 164 hits, 27 doubles, six triples, and seven home runs in 144 games played. In the field, he committed seven errors in 309 total chances. In 1933, he split the season with the Indians and the Class-A
Fort Worth Cats of the
Texas League. With Indianapolis, he batted .281 with 41 hits, eight doubles, two triples, and two home runs in 44 games played. In 75 games with Fort Worth, he batted .325 with 89 hits, 17 doubles, seven triples, and four home runs. Combined between the two clubs that year, Rosenberg committed eight errors in 240 total chances. In 1934, Rosenberg spent his final season with the Indians. He batted .329 with 148 hits, 18 doubles, 11 triples, and two home runs in 126 games played. He committed 11 errors in 269 total chances as an outfielder that year.
Return to the Pacific Coast League . In December 1934, the Indians sold Rosenberg to the Double-A
Sacramento Senators of the PCL. Sacramento were affiliated with the
Brooklyn Dodgers in 1935, making Rosenberg a member of their minor league organization. That season, he batted .354 with 201 hits, 27 doubles, 16 triples, and 10 home runs in 151 games played. He was tied for third in the PCL that season in triples, and was eighth in batting average. In the field, he had a .981
fielding percentage. The Sacramento Senators sold Rosenberg to the Mission Reds in November 1935 due to financial restrictions. Before the 1936 season, Rosenberg played a charity game in San Francisco, which benefited
semi-professional baseball players who sustained injuries on the field. In his first season with the Reds, he batted .334 with 223 hits, 33 doubles, 15 triples, and three home runs in 172 games played. Rosenberg was second in the PCL in triples that season. He was also fourth in hits, and ninth in
total bases (295). Defensively, he compiled a .969 fielding percentage in the outfield. Rosenberg was traded to the
Portland Beavers PCL franchise before the 1938 season by the
Hollywood Stars, formerly the Mission Reds, in exchange for
Tommy Thompson. In his first season with Portland, he batted .320 with 184 hits, 37 doubles, eight doubles, and four home runs in 154 games played. Rosenberg had a .286 fielding percentage that season, which would later prove to be a career high. Before the start of the 1939 season, he was dubbed a holdout for not signing his contract with Portland. Rosenberg eventually signed with the Beavers, and compiled a batting average .331 with 214 hits, 45 doubles, five triples, and eight home runs in 172 games played. He was fourth in the PCL in hits, fifth in doubles, and tenth in total bases. Rosenberg spent his final season with the Beavers in 1940. He batted .314 with 207 hits, 28 doubles, six triples, and four home runs in 177 games played on the season. He was sixth in the league that year in hits. He a .976 fielding percentage. In 1941, the Hollywood Stars purchased Rosenberg from the Portland Beavers. He was selected to the 1941
PCL All-Star Game. That season, he batted .286 with 58 runs scored, 120 hits, 31 doubles, two triples, one home run, 55
runs batted in (RBIs), and nine
stolen bases in 120 games played. As an outfielder, he committed six errors in 124 total chances. He did not play professional baseball in 1942. Before the 1943 season, Rosenberg signed with the Double-A
San Francisco Seals of the PCL. On the year, he batted .362 with 11 runs scored, 34 hits, four doubles, one triple, and 18 RBIs in 26 games played. In 1944, he was diagnosed with what was reported as being a "minor chronic disorder" which caused him to need surgery. Later that year, Rosenberg announced that due to the time-consuming day-to-day operations of his
trucking business, he would not be able return to the Seals, although he wished to. ==Later life==