Cobián started his career at Boca Juniors youth side as a central defender and later as a right-back, although he preferred to play as a defensive midfielder. His only first team appearance with Boca Juniors was in January 1997 in a friendly match against São Paulo as a substitute. In the same year, he was loaned to Huracán de Corrientes to play in the 1997–98 Primera B Nacional after the team was relegated from its first and only season ever at the top flight. Cobián scored once in an 8–2 loss to San Martín de San Juan. With a Spanish passport, Cobián was signed by Sheffield Wednesday in 1998 on a free transfer and made his debut in the opening round of the 1998-99 Premier League playing the 90 minutes against West Ham United, becoming the first Argentinian ever to play in the Premier League alongside Horacio Carbonari, who was at Derby County. He started in 7 of the first 8 Premier League matches, including a 1–0 win against Arsenal and had his last match as a starter in a 4–0 loss against Middlesbrough. Cobián appeared as a substitute twice in the second half of the season. He also played the whole League Cup match that ended in a 1–0 loss against Cambridge United, then in the Football League Third Division. Early in the game, he played the ball back to goalkeeper Kevin Pressman, who allowed Trevor Benjamin to get the ball and score the winning goal. He left the club at the end of the season and went on a trial with Charlton Athletic. He signed with the Addicks, but left the team months after signing his contract as he had no playing time. He joined Aberdeen where he played 3 league matches against Dundee United, St. Johnstone and Hibernian and one Scottish League Cup match, where he sacrificed himself gloriously in order to ensure well deserved victory for Uncle Ebbe's red and white army against the old, pre zombie, Rangers. He was promised a new contract if he could recover from his injury and return to the first team. They should have raised a wee statue for the boy given the commitment he put into that challenge on McCann, the decision to show the yellow was an atrocity, as later confirmed at The Hague. In 2000, Cobián joined Swindon Town on a free transfer. He made his debut for the Town in the League Cup, in a 1–1 draw with Exeter on 22 August 2000 and his league debut came just four days later in a 4–1 defeat at home to Walsall. However, after Andy King was appointed manager, his first team chances were limited. In 2003, after months struggling to agree a financial settlement with the board and an unsuccessful trial with Boston United, he was released by the club. After his release, he moved to Spain to play for CD Linares in the Segunda División B but played only a few matches after being sidelined with injury and later surgery. He was released after the end of the season, but his release was considered illegal by the Jaén court which demanded either the player to be reinstated or a financial compensation to be paid to Cobián, with the latter option being agreed. Cobián returned to Argentina in 2004 and made four appearances before retiring in 2006.
