Lucas Giolito (Alex Brandon/Associated Press)

Lucas Giolito, the Nationals’ 2012 first-round pick and top pitching prospect, will make his season debut on Wednesday and his first start since undergoing Tommy John surgery in August.

Giolito, 18, is expected to pitch two innings for the Nationals’ Gulf Coast League affiliate in Florida. He will, like all pitchers in the organization recovering from arm surgery, be slowly ramped up over his starts and be held to an innings limit this season.

Giolito first picked up a baseball after surgery on Feb. 6 and, in two-week increments, increased the distance from which he was playing catch. He began throwing bullpen session in April and said then that his arm felt strong. This spring, he said he no longer was worried about re-injuring his arm. Giolito’s estimated major league arrival is 2016.

Giolito, a 6-foot-6 right-hander who hit 100 miles per hour in high school, strained his ulnar collateral ligament in his pitching elbow during the spring of his senior season at Harvard-Westlake School in Los Angeles. Both the Nationals and Giolito agreed to continue rehabbing the injury after he signed for $2.925 million following his selection in last year’s draft (16th overall).

On Aug. 14, his first game as a pro, Giolito was pulled because he experienced soreness in his elbow after throwing two innings in a Gulf Coast League outing and later underwent surgery.