 Castro returned to Porto for 2010–11, but was soon deemed surplus to requirements by new manager André Villas-Boas as practically all Portuguese players.In January 2011, after having amassed 106 minutes in six competitive matches, he was loaned to Sporting de Gijón in Spain, making his La Liga debut on the 23rd by playing one minute in a 1–0 home victory over Atlético Madrid.Castro managed to feature regularly for the Asturians during his spell, starting 11 times and scoring against RCD Mallorca (4–0, away) and Getafe CF (2–0 at home), in an eventual escape from relegation.