He played solely in Andalusia in a 17-year professional career, with Betis and Recreativo, appearing in more than 200 matches in both La Liga and the Segunda División.

[2] Out of his 12 years at the club eight were in La Liga, and he appeared in 203 games in that division, scoring two goals; in the 1996–97 season, he contributed 36 matches to help to a fourth-place finish.

[7][8] In the 2010–11 season, Merino cut ties with Betis and returned to Recre as assistant to Pablo Alfaro – a former Sevilla FC defender – with the club in the Segunda División.

[12] On 25 November, after Julio Velázquez's dismissal from the first team, he was named interim manager;[13] he remained in charge for four league matches, achieving as many wins before being replaced by Pepe Mel and returning to his previous duties.

[17] On 28 December, he took over at second-tier club Gimnàstic de Tarragona in the place of Vicente Moreno,[18] but was himself relieved of his duties the following 20 May as the team was still in the relegation zone.