He began his career in 1994 with Bilbao club Leioa, then in the Primera División de Bizkaia in the sixth tier of Spanish football.

He scored his first Barakaldo goal in the 83rd minute to give his side the lead, and added two more before the final whistle to secure a remarkable hattrick and a 4–1 win.

Mikel played in five of the games, but the 1–0 home loss to group winners Elche would prove to be his last for Barakaldo, as he left the club at the end of the season.

[2] The highlight was scoring a hattrick at El Malecón in a 5–0 win over Gimnástica de Torrelavega on 20 September, but by the end of the season he was ready for a new challenge.

[12] Mikel's good form earned him a move up to the Segunda División, as he left his native Basque Country for the first time to join Lleida in Catalonia.

[13] After four clubs in six years, Mikel finally found some stability by joining Lleida's Segunda División rivals Albacete Balompié in the summer of 2000.

[2] He was a regular starter immediately, making his debut in Albacete's first game of the season, a 1–0 home win over Tenerife at Estadio Carlos Belmonte on 2 September.

Despite regular appearances, he had to wait until 21 February to score his first Albacete goal, a consolation in a 3–2 loss to Racing de Ferrol at A Malata.

His form picked up from there, however, and he finished the season with six goals in 33 appearances, including a brace in an excellent 4–1 win over Córdoba at Estadio Nuevo Arcángel on 10 June.

27 appearances in all competitions yielded 3 goals for Mikel, which helped Albacete to 3rd place in the league and promotion back to La Liga after seven years away.

[2] Mikel made his La Liga debut at home on 14 September, and it was something of a baptism of fire as he came off the bench against Barcelona in a match which Albacete ultimately lost 2–1.

Five days later Albacete faced Tenerife at Estadio Heliodoro Rodríguez López in their final match of the season, and the 1–1 draw proved to be Mikel's last for the club.

[2] He featured in four of Alicante's first five matches of the season: a 1–0 loss away to Osasuna B, victories away against Villajoyosa and at home against Eldense, and their Copa del Rey elimination at the hands of his former club Lleida.