[2] Velazco's first club was Argentine Primera División side River Plate, he played in the youth ranks for nine years.
[1] He appeared on the substitutes bench fifteen times in all competitions during the 2016 and 2016–17 seasons, prior to making his professional debut on 25 May 2017 in River Plate's final Group 3 match in the 2017 Copa Libertadores versus Independiente Medellín.
[6][7] He returned to River at the end of the year, prior to securing a loan move to Primera B de Chile with Cobreloa in January 2020.
[2] His debut arrived on 13 January in the preceding campaign's promotion play-offs, delayed from the end of 2019, as his new side lost to Deportes Temuco at the first hurdle.
[2] He appeared twenty-six times in 2020, which preceded Cobreloa signing Velazco permanently; penning a four-year contract.