Carson is expected to leave the post on April 8. He is reportedly resigning along with his senior adviser Morgan Plummer.
Carson cited “low likelihood of confirmation” and “reduced time left in the administration” as reasons for his decision to resign.
The Force of the Future personnel reform includes such widely-debated decisions as opening combat positions to women.
The Sicilian city Trapani will be the operational center for the exercise that begins Wednesday and runs through early November, extending into Spain, Portugal and adjacent waters.
Eleven Colombian military personnel were killed on Friday when their transport plane suffered motor failure and crashed in the northern province of Cesar, killing all on board, according to a statement from the Air Force.
The burned hulk of the plane was found near the town of Codazzi, about 600 km (372 miles) northeast of Bogota near the border with Venezuela.