Long-serving captain Xabi Prieto has agreed a four-year contract extension with Real Sociedad, the La Liga outfit have announced. The highly-rated 28-year-old, who came up through the youth ranks at Sociedad and has made over 250 first-team appearances for his hometown club, is now committed to the Basque outfit until 2017. A statement on the Sociedad website read: \"Real Sociedad and Xabi Prieto have reached an agreement to renew his contract. The new agreement is for four years and means the midfielder will be tied to Real Sociedad until 30 June 2017.\" Prieto told his club\'s website: \"Of course I would like to retire at Real and today I have taken a step further towards that dream.\" The news is another boost for Sociedad, who have dragged themselves off the foot of La Liga and out of the relegation zone with an unbeaten five-match run, having picked up one point from a possible 21 previously.