A youth academy graduate of Defensor Sporting, Fratta made his professional debut on 6 September 2015 in a 3–2 league win against rivals Danubio. Playing whole 90 minutes in the match, he opened his team's tally with a goal in fourth minute.[2] He made his continental debut on 2 October 2015 in a 0–0 draw against Argentine side Lanús.[3]