Bought by Athletic Bilbao from lowly Peña Sport FC in 2003, Vélez spent time with the club's B and feeder teams, subsequently being loaned to neighbours Barakaldo CF in Segunda División B. He made his debut for the main squad of the latter on 26 August 2007, in the goalless La Liga home draw against CA Osasuna. After spending the second part of the 2007–08 seasonon loan to Segunda División's Hércules CF, where he appeared significantly – after his debut with the Alicante side, he managed to play, in the same season, in the three major levels of Spanish football – Vélez was definitely promoted to Bilbao's first team for 2008–09. He was regularly played during the league campaign and, on 9 May 2009, scored the game's only goal as the Basques defeated Real Betisat home. During the first part of 2010–11, Vélez only made five official appearances for Athletic, all as a second-half substitute. On 19 January 2011 he moved to CD Numancia from division two on loan, reuniting with former Athletic teammate – and namesake – Iñigo Vélez; in late July, after being deemed surplus to requirements by new manager Marcelo Bielsa, he terminated his contract at the San Mamés Stadium and signed for Girona FC also in that level, with his former club having a rebuying option at the end of the 2011–12 season. On 3 October 2011, during an away league fixture against Xerez CD, Velez collided with opponent goalkeeperToni Doblas, suffering an extremely serious injury to his right knee which sidelined him for the rest of the campaign. In July 2013 he signed with Deportivo Alavés, freshly promoted to the second tier. On 13 July 2015, Vélez agreed to a one-year deal with fellow league team CD Mirandés. He returned to the third division prior to the start of 2016–17, joining CD Tudelano. In November 2017, following a match against his former club Mirandés where he was sent off for kicking an opponent, Vélez was banned for four games. Upon appeal, it was later reduced to two. On 24 June 2019, the 34-year-old Vélez returned to Peña Sport.
