On 28 April 2012, Martín was first called up by the main squad, being selected for a Segunda División game against Deportivo de La Coruña.[1] He made his competitive debut the following day, coming on as an 84th-minute substitute for Dani Bautista in an eventual 2–0 home win.[2]
Martín scored his first professional goal on 24 August 2014, opening the 1–1 home draw against Deportivo Alavés.[5] In 2015–16, he contributed 28 appearances as the side were promoted to La Liga for the first time ever.
Martín made his debut in the Spanish top flight on 22 August 2016, starting in a 1–0 away victory over RC Celta de Vigo.[6] On 7 July of the following year, he signed a two-year deal with Granada CF.[7]