Valenzuela is a youth exponent from Newell's Old Boys, having joined the club at the age of 14. He broke into the first team at the age of 17, making his league debut on 6 February 2016 against San Martín de San Juan in a 2–1 away defeat in Rosario. While never becoming a permanent feature with the first team after his break through, Valenzuela made 13 league appearances for the club, along with 3 cup appearances, over three seasons. Because of his youth and lack of playing time, on January 26, 2018, Valenzuela was sent on a year long loan to ColumbusCrew SC of Major League Soccer, with an option to buy at the end of the loan. After a successful season with Columbus in MLS, the Crew exercised their purchase option at the end of the 2018 season and Valenzuela ended his time with his boyhood club.
Valenzuela made his debut for Columbus on 3 March 2018, playing 90 minutes in a 2–0 win against Toronto FC. He scored his first professional goal on 24 March 2018 in a 3–1 win against D.C. United. Over the course of the season he made 30 appearances with 29 starts. Valenzuela was an immediate success for Columbus, and over the course of the season, became one of the league's top attacking defenders. Valenzuela completed 27 crosses from the run of play, first among defenders in the league, and was among the best tacklers in the league winning 57 out of 87. Moreover, the defender also scored one goal and produced six assists. On 21 December 2018, it was announced that Valenzuela's immensely successful first season in Columbus had caused the team to exercise their purchase option signing Valenzuela permanently ahead of their 2019 season. However, despite an encouraging preseason, Valenzuela suffered a tear in his ACL during training and would be out for the entirety of the 2019 season.
Personal life
Before moving to Columbus, Ohio Valenzuela lived with his entire family in Argentina. He admitted that there was a learning curve that comes with moving from Argentina to the United States, while also living by himself for the first time. However, he believes that these experiences will help him become a better person and a stronger footballer.
