Oswaldo Antonio Mairena
- Bats Left, Throws Left
- Height 5' 11", Weight 165 lb.
- Debut September 5, 2000
- Final Game September 28, 2002
- Born July 30, 1975 in Chinandega, Chinandega, Nicaragua
Oswaldo Mairena has been a long-time member of the Nicaraguan national team.
In the 1994 Baseball World Cup, Mairena was 1-0 with a 1.29 ERA for the Nicaraguan team which just missed out on a medal. He four-hit the French national team and struck out 8 in a shutout. In the Gold Medal game, he relieved Marvin Zelaya in the 5th inning with a 5-0 deficit against the Cuban national team. Mairena allowed 3 runs, 2 earned, in five innings, for a decent showing against the dominant Cubans. He was 1-1 with a 5.40 ERA in the 1995 Intercontinental Cup, won a Silver Medal with Nicaragua in the 1995 Pan American Games and played in the 1996 Olympics.
In the 2006 America qualifiers for the 2008 Olympics, Mairena was 1-2 with a 1.93 ERA as Nicaragua's ace. Nicaragua did not qualify for the Olympics but they did qualify for the Pan-American Games in 2007. Mairena was 1-0 with a 1.93 ERA in the 2006 Central American and Caribbean Games.
He struggled in the 2007 Pan-American Games in a loss to Team USA, allowing 4 walks, five hits and four runs in 3 2/3 innings. He got a no-decision in relief. He was the lone player with major league experience on Nicaragua, which shared a Bronze Medal with Mexico (with at least four former big leaguers) after their final game was rained out.