Born in A Coruña, Galicia, Jason played for Deportivo de La Coruña's youth setup, where a coach gave him his moniker to distinguish him from two other boys called David; he was nicknamed after British Formula 1 driver Jenson Button because of his speed.[2] Having been released after two seasons, he finished his development at Levante UD.[3] He began playing as a senior with the latter's reserves in 2012–13 in the Segunda División B, and on 1 July 2013 signed a new two-year deal with the club.[4]
On 25 August 2013, Jason made his La Liga debut, featuring one minute in the 0–0 home draw against Sevilla FC.[5][6] On 14 August 2014, he moved to Villarreal CF B on loan.[7]
On 26 January 2015, Jason was recalled by Levante, and was registered with the B side but assigned to the first team.[8] On 31 August, he joined Albacete Balompié of Segunda División on loan for one year.[9] He scored his first goal as a professional on the following 3 January, in a 2–2 draw against SD Ponferradina at the Estadio Carlos Belmonte.[10]
Jason returned to the Estadi Ciutat de València for 2016–17, and scored the game's only goal in an away win over CD Numancia on 21 August 2016.[11] He added a further nine during the campaign, helping his team to return to the top flight after one year out.[12]
Valencia
On 1 July 2019, free agent Jason agreed a three-year contract with Valencia CF.[13] On 2 September, however, he was loaned to fellow top-tier club Getafe CF for one year.[14] He featured in just over half of the matches as the team from the Community of Madrid finished in eighth position,[15] and scored once on 26 September in a 3–3 draw away to his parent club.[16]
Jason made his debut for Los Che on 19 September 2020, as a half-time substitute in a 2–1 opening day defeat at RC Celta de Vigo.[17][18]
^Álvarez, Fernando (19 September 2020). "Aspas es el martillo pilón del Celta" [Aspas is Celta's steam hammer]. Marca (in Spanish). Retrieved 18 November 2020.
^Iñigo, Iñaki (20 January 2022). "Dos inicios demasiado grises" [Two debuts that were too grey]. Noticias de Álava (in Spanish). Retrieved 22 April 2023.