 He made his official debut for the B-team on 4 September 2011, starting in a 4–0 away win against Cartagena at the age of 15 years and 349 days and becoming the youngest player ever to appear in a Segunda División game.On 23 February 2013, Grimaldo suffered a serious knee injury, being ruled out for the remainder of the season.He returned to action in January of the following year, appearing in 14 matches to help his team finish in third position.