On January 10, 2018, Thiaw was selected 35th overall by the San Jose Earthquakes during the 2018 MLS SuperDraft.[4] He was officially signed by the club on March 1, 2018, and immediately sent on loan to San Jose's USL affiliate Reno 1868 FC, alongside fellow SuperDraft pick Danny Musovski.[5] Thiaw made his first professional appearance on March 24, 2018, as a 77th minute substitution for Brian Brown during Reno's 1–1 draw with Las Vegas Lights FC.[6]
Thiaw was released by San Jose at the end of their 2018 season.[7]