Sosa began his playing career in 2005 with Independiente. He made his league debut on 20 March 2005 in a 2–1 away defeat to Boca Juniors. In 2006, he had a loan spell with San Martín de San Juan but returned to the Independiente where he played until 2009 making 80 league appearances and scoring 13 goals.

During the 2009 winter transfer window he joined Argentinos Juniors under new manager Claudio Borghi where he started well with 3 goals in his first 6 games for the club. His good form in the Apertura 2009 helped the club to a creditable 6th-place finish and in the Clausura 2010 he was the top scorer for the club with 9 goals in 17 appearances helping the club to win the Primera División for the first time since 1985.

Sosa was given the number 18 shirt at Kamil Ocak Stadium. He made his first Süper Lig appearance on 13 July 2010, in Gaziantepspor’s fourth game of the season, in the match away to Kasımpaşa. Sosa scored his first league goal for Gaziantepspor against Bucaspor.

On 7 January 2013, Sosa joined Universidad Católica.

On December 26, 2013, Sosa was transferred to Mexican club Club Universidad Nacional. He had limited game time in his first tournament, scoring just 2 goals, but the return of Memo Vazquez saw an increase in opportunities resulting in an increased goal tally year on year. Sosa scored 5 goals in his second tournament with the club and found the net 7 times in his third tournament, the Clausera 2015. The Apertura 2015 saw Sosa become the star man for Pumas and became only the 5th pumas player to score 10 or more goals in the short tournament format, scoring 10 goals. He also added 7 assists during the regular season. On December 9, 2015 Club Universidad Nacional tied Sosa down for another three years to the club.

On 18 June 2016, Sosa arrived to Monterrey to join Tigres UANL. On 10 July, he made his debut as a starter playing against Pachuca FC in the 2016 Campeón de Campeones Cup. He scored the winning goal at 25′ after a cross from Javier Aquino giving Tigres their first Campeón de Campeones championship. He scored his first goal with Tigres in Liga MX on July 30, 2016, the final goal of the 3-0 victory over América at the Estadio Azteca.