A 2011 graduate of Catholic High School (LA), Aaron was voted “Mr. Baseball” for the state of Louisiana during his senior season. He attended Louisiana State University and was honored as the 2014 National Pitcher of the Year by the College Baseball Foundation. In 2014, Aaron was a Golden Spikes Award finalist, named First-Team All-American, SEC Pitcher of the Year and First-Team All-SEC.
At 22 years and 329 days old on April 28, 2016 at Washington, Aaron became the youngest Phillies starting pitcher since 1973 (Dick Ruthven, 22 years, 32 days on7/1 at St. Louis) to toss 7.0 or more scoreless innings while allowing two hits or fewer. His 0.85 WHIP was the lowest of any Phillies starter through their first seven starts of a season since Curt Schilling (0.84) in 1998.He had a career-best 23.0-inning scoreless streak from April 22 to May 8, the longest by a Phillies starter since Cole Hamels (24.2 IP), June 1-24, 2014, and tied for the longest in the National League in ’16 (with three others). Aaron went 7.0 innings or more and allowed one earned run or none in nine of his first 21 career starts, the most ever by a Phillies starter in their first 21 career games. He made nine consecutive quality starts (4/22-6/5/16), the longest streak by a Phillies’ starting pitcher since Cole Hamels tossed 10 consecutive quality starters in 2013 (7/26- 9/14).
Aaron was the first player drafted by the Phillies to make his major-league debut the very next season since Pat Combs in 1989. He was the seventh overall selection in the 2015 amateur draft.