Somoza began his professional career playing for
Vélez Sársfield in the
Argentine Primera in 2001. He played for the club for five years, and was a key player in the
2005 Clausura tournament winning team. In 2006, Somoza was transferred to
La Liga club
Villarreal CF on a five-year contract. He joined fellow countrymen
Juan Román Riquelme,
Gonzalo Rodríguez,
Rodolfo Arruabarrena,
Fabricio Fuentes and
Mariano Barbosa. However, Somoza spent only one season with Villarreal, being loaned in August 2007 to
Real Betis. The Argentine midfielder was presented to the media on 14 August and made his first appearance in a friendly against
Real Zaragoza two days later. His first competitive debut came in the season against
Recreativo Huelva, on 26 August. After his second season in Spain, Somoza returned to Argentina for the
2008–09 season to play again for Vélez Sársfield. During the
2009 Clausura, he was part of the squad that won the Argentine league championship, but did not participate in any of the games due to an injury he had suffered at the end of the previous tournament. Somoza scored for the first time after his injury on a 1–1 draw with
Lanús, on the 9th fixture of the
2009 Apertura. On 14 January 2011, Somoza signed on to play with
Boca Juniors. With the
xeneizes Somoza won the
2011 Apertura and
2012 Copa Argentina and was runner-up of the
2012 Copa Libertadores. For the
2013–14 Argentine Primera División season Somoza joined
Lanús. With his new club the midfielder won the
2013 Copa Sudamericana, playing all 10 games. In 2015, Somoza agreed on a free transfer to Vélez Sarsfield, his third spell with the club. ==International career==