On 19 October, Félix suffered an ankle injury against Valencia, after a rash challenge by Dani Parejo, leaving his team with only ten men on the pitch, as his coach Diego Simeone had already made the maximum number of allowed substitutions. Initially, Simeone thought that Félix's injury was not too serious, until the club's medical team revealed that the ankle injury could be severe, leading him to be sidelined for one month. Félix made his return on 23 November in a 1–1 away draw against Granada. During this time, Félix was one of the 30 candidates who was nominated for the 2019 Ballon d'Or.