2018 (S2): Vargas made his USL debut on May 12 against Portland Timbers 2. He started the match at attacking midfield and played 55 minutes.
Vargas signed with S2 after being part of the Sounders Academy since 2016 after initially signing from partner club Central California Aztecs earlier that year. He had 19 goals and 26 in 35 appearances across all competitions in 2018 before signing with S2. Vargas netted five goals in 21 games for the Sounders U-15/16 team in 2017.