Acquired by the Philadelphia Union on Jan. 15, 2014 from Argentinos Juniors (Primera Division) after a return from Atlante of the Mexican League.
2014: Appeared in 26 games, starting 23, while logging 1,889 minutes. He had 11 assists – the second-most in a single-season in franchise history. He also scored two goals. Maidana's impact was immediate, assisting on the lone goal in the season opener against Portland on March 8. He then scored his first career goal on May 17 against Sporting Kansas City. Maidana assisted on all three goals in a 3-3 draw against Vancouver on June 7 and was named to the MLS Team of the Week by MLSSoccer.com for his performance. He also assisted on the lone Union goal in the U.S. Open Cup final on a free kick to Maurice Edu. His play never dropped, as he had arguably his best game of the year while notching a pair of assists in Philadelphia’s 2-1 victory over Sporting Kansas City on Oct. 18 leading to his second MLS Team of the Week honors.
2011-12: Spent two seasons playing for Rangers (Primera Division) appearing in a total of 31 games. Throughout these two seasons, Maidana recorded two (2) goals.
2010-11: While on loan, Maidana appeared in 13 games for Huracan (Primera Division), logging 903 minutes.
2010: Appeared in 10 games, logging 408 minutes for Spartak Moscow of the Russian Premier League.
2008-09: Played for Recreativo Huelva then of the Spanish first division (La Liga). He appeared in six matches scoring a goal and adding a pair of assists.