CHICAGO – Mark Appel has officially started his path toward the major leagues. The No. 1 overall pick of the 2013 MLB amateur draft traveled Sunday to the Astros’ spring-training home in Kissimmee, Fla. He’ll begin a throwing program after meeting with Astros trainers and the organization’s pitching coordinator. It’s been three weeks since Appel last threw, Astros general manager Jeff Luhnow said, and the club wants him to be comfortable with his schedule before taking the mound. Appel will likely collect a few innings during simulated games, spend about 10 days in Kissimmee, then join short-season Tri-City in Troy, N.Y. If the schedule holds, Appel could make his pro [.]