Perez cancelled his contract with Cordoba to make the free transfer to The Reebok.
Bolton boss Sam Allardyce believes the 24 year old will provide cover in midfield for the second half of the season.
"We have signed Oscar to strengthen numbers in the crucial midfield area," Allardyce told the club's official website.
"He has played most of his career in the lower leagues in Spain and will mainly get his chance in the reserves and potentially in the first team later this season.
"He has a great attitude to training and with the right application can develop his career in England."