Lisbon has been all set to sign the 23-year-old earlier this month as part of a player exchange for Hugo Viana, however the deal collapsed when Newcastle United swooped in at the last minute to sign the Portuguese starlet.
Contreras spent the whole of last season on loan with Osasuna, making 31 appearances for the club, after Celta agreed his release due to the club already having a full quota of non-EU players.
Although Vigo are willing to let the young defender leave the club, they may opt to keep the South American if Benni McCarthy and Valery Karpin leave freeing up additional places in their non-EU quota.
McCarthy has been constantly linked with a possible move to Middlesbrough, whilst Karpin is out of contact is a reported target for Blackburn Rovers.
