Analysis of information sources in references of the Wikipedia article "Roberto Clemente" in English language version.
On July 25, 1956, Roberto Clemente did something that may have been done only once in the history of baseball. And I was there to see it
Roberto Clemente Walker was born on August 18, 1934, to Melchor Clemente and Luisa Walker de Clemente in Carolina, which is slightly east of the Puerto Rican capital of San Juan. Roberto was the youngest of Luisa's seven children (three of whom were from a previous marriage).
When he was 14 years old Roberto joined a softball team organized by Roberto Marín, who became very influential in Clemente's life. Marín noticed Roberto's strong throwing arm and began using him at shortstop. He eventually moved him to the outfield.
Throwing the javelin strengthened his arm and helped him in other ways, according to one of his biographers, Bruce Markusen: "The footwork, release, and general dynamics employed in throwing the javelin coincided with the skills needed to throw a baseball properly. The more that Clemente threw the javelin, the better and stronger his throwing from the outfield became."
Brooklyn general manager Buzzie Bavasi later acknowledged that the team hoped to hide Clemente so no other team would see his incandescent talent and draft him — as Pittsburgh did after the season... Researcher Stew Thornley found that Clemente was platooned for much of the season, starting only against left-handed pitchers, just as Macon platooned other outfielders.
Macon always denied it, but he was not believed... "I never had any orders not to play Clemente," Macon said.
By the end of the 1954 season, it had become clear to Bavasi and the rest of the Brooklyn organization that other teams were interested in Clemente. However, Bavasi said he still wasn't ready to give up... he went to Branch Rickey... to get Rickey to agree draft a different player, pitcher John Rutherford, off the Royals' roster. However, Bavasi was dismayed to learn two days later that the deal was off and that the Pirates were going to draft Clemente.