[3][4][5][6] He was promoted into their first-team, aged sixteen, towards the end of the 2018–19 campaign, with the winger initially appearing as an unused substitute for a Copa Sudamericana second stage encounter with Rionegro Águilas on 21 May 2019.
[7][8] He was again on the bench for the second leg on 28 May, with Velasco subsequently making his professional debut at the Estadio Libertadores de América; replacing Jony in added time.
[7] Velasco, aged eighteen, netted his opening domestic goals in the Copa de la Liga Profesional in November and December against Colón and Argentinos Juniors respectively.
[7] On February 1, 2022, Velasco was announced by FC Dallas as its costliest signing ever at that time in a four-year deal reported at $7 million with potentially an additional $1.7M based on incentives.
[10] Velasco represented Argentina at U15 and U17 level, scoring one goal in four appearances for the latter at the 2019 South American Championship in Peru; which they won.