for inducing an increased amount of whiffs. At the conclusion of the season, the Register named Sandoval to its All-County second team and he was also selected to the All-CIF-SS first team. On August 10, Sandoval partook in the Perfect Game All-American Classic at Petco Park in San Diego, pitching of an inning and recording a strikeout. In November 2014, his senior year in high school, Sandoval signed his National Letter of Intent to play college baseball for Vanderbilt University. On March 31, 2015, Sandoval threw a two-hit shutout against top-ranked San Clemente High School. On May 11, he switched his collegiate commitment from Vanderbilt to the University of Southern California. Sandoval finished his senior season at 9–3 with a 0.97 ERA. On June 6, Sandoval threw a complete game while giving up two hits and one unearned run to aid Mission Viejo in its 3–1 victory over Chino Hills High School in the CIF-SS Division 2 championship game. Following the season, he was selected to the Register's All-County first team and was named the CIF-SS Division 2 Most Valuable Player. Professional career Houston Astros organization Sandoval was selected by the Houston Astros in the 11th round of the 2015 Major League Baseball draft, the 319th overall pick. Sandoval initially signaled intent to eschew his draft selection and attend USC, but he ultimately signed with the Astros after they offered him a $900,000 bonus; at $800,000 over-slot, it was the largest bonus given to a player picked beyond the first 10 rounds of the 2015 draft. Astros scouting director Mike Elias called Sandoval a "premium" prospect and noted that his scouting department had been closely following his development throughout the spring. After signing, Sandoval made his professional debut that season in the Rookie-level Gulf Coast League (GCL) with the GCL Astros. In his first professional game on August 1, 2015, he pitched two innings while giving up eight hits and five runs (four earned) and striking out three against the GCL Phillies. He finished his first professional season at 0–3 with a 6.08 ERA in six starts. On June 22, 2016, the Astros assigned Sandoval to the Rookie-level Greeneville Astros of the Appalachian League, where he pitched to a 2–3 record and 5.30 ERA in 13 games (eight starts). On May 14, 2017, Sandoval was promoted to the Class A-Advanced Buies Creek Astros of the Carolina League. In one start