MLB, citing security concerns caused by the threat of an American-led war with Iraq, moved next week's series between the Oakland Athletics and Seattle Mariners to the US.
The move is the first schedule change involving a major US sports event related to the potential Middle East conflict.
The two games, originally set for March 25-26, will now be played in Oakland, California, on April 3 and June 30.
MLB commissioner Bud Selig stated: "Given the uncertainty that now exists throughout the world, we believe the safest course of action for the players involved and many staff personnel who must work the games is to reschedule the opening series. It would be unfair and terribly unsettling for them to be half a world away - away from their families - at this critical juncture."
Baseball's regular season now will begin with the defending World Series-champion Anaheim Angels hosting the Texas Rangers on March 30.
Both the Mariners and the Athletics were supposed to play exhibition games against teams from Japan's major leagues this weekend, before opening the regular season next week at the Tokyo Dome.
"With world tensions so high, this is the prudent course of action," players union Executive Director Donald Fehr said. "We do regret, though, having to take it."
The season-opening series for Major League Baseball (MLB) has been moved from Toyko in Japan back to the US in light of the impending war in the Middle East.
