Yes, the U.S. military forces were pre-positionned to be deployed to the island.
What is particularly disturbing is the reaction of the United States. While the Western media are immersed in a controversy over the violation of Haiti’s sovereignty, the Latin American media are perplexed about the swiftness of GI deployment: as of the first day, more than 10000 soldiers and contractors arrived in Haiti. This logistical feat can be easily explained since these troops were already pre-positioned in the context of a military exercise. Under the orders of General P.K. Keen, Military Deputy Commander of U.S. Southern Command (USSOUTHCOM), they took part in an excercise simulating a humanitarian operation in Haiti after a hurricane.