The 1958 major league baseball season began on April 14, 1958. The regular season ended on September 28, with the Milwaukee Braves and New York Yankees as the regular season champions of the National League and American League, respectively. The postseason began with Game 1 of the 55th World Series on October 1 and ended with Game 7 on October 9. In the second iteration of this World Series matchup (and a rematch of the previous year), the Yankees defeated the Braves, four games to three, capturing their 18th championship in franchise history, since their previous in . Going into the season, the defending World Series champions were the Milwaukee Braves from the season.
The 25th Major League Baseball All-Star Game was held on July 8 at Baltimore Memorial Stadium in Baltimore, Maryland, home of the Baltimore Orioles. The American League won, 4âÂÂ3.
Following the relocation trend that began in , the National League's Brooklyn Dodgers and New York Giants moved from New York, New York (Brooklyn and Manhattan, respectively) to California (Los Angeles and San Francisco, respectively), becoming the fourth and fifth teams to relocate in the relocation era and leaving New York a one-team city. The moves to California marked the first time major-league teams played on the West Coast. The National League exodus from New York would go on to inspire the proposed Continental League the following year, which pressured the two existing leagues to begin expansion. New York went without a National League team for four seasons, until the expansion New York Mets began play in .
On June 6, the Detroit Tigers became the 15th team in professional baseball to break the color line when they fielded Ozzie Virgil Sr.
The 1958 schedule consisted of 154 games for all teams in the American League and National League, each of which had eight teams. Each team was scheduled to play 22 games against the other seven teams of their respective league. This continued the format put in place since the season (except for ) and would be used until in the American League and in the National League.
American League Opening Day took place on April 14, featuring the Boston Red Sox and Washington Senators, while National League Opening Day took place the following day, featuring all eight NL teams. This continued the trend from the previous season which saw both leagues opened on different days. The final day of the regular season was on September 28, which saw fourteen teams play. The World Series took place between October 1 and October 9.
The 1958 season saw the following rule changes:
The postseason began on October 1 and ended on October 9 with the New York Yankees defeating the Milwaukee Braves in the 1958 World Series in seven games.
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The Los Angeles Dodgers, newly relocated from their long-time home in Brooklyn as the Brooklyn Dodgers, leave Ebbets Field after playing there for 45 seasons, moving into Los Angeles Memorial Coliseum where they would play for four seasons through .
The San Francisco Giants, newly relocated from their long-time home in New York City as the New York Giants, leave the then-current iteration of the Polo Grounds after playing there for 67 seasons (75 seasons including previous iterations of the Polo Grounds,) moving into Seals Stadium where they would play for two seasons through the following season, .
CBS and NBC aired weekend Game of the Week broadcasts. NBC began airing a special regional feed of its games in the southeast. The All-Star Game and World Series also aired on NBC.