Celtic defender Efrain Juarez has returned from Real Zaragoza following a season-long loan deal.
The Mexico right-back played 19 matches with the Spanish side after failing to earn a regular spot with Celtic.
The 22-year-old made 11 starts and nine sub appearances under Neil Lennon after being bought for £3m in 2010.
Lennon said: "He will provide us with some more options, particularly with Beram [Kayal] being out injured, as we look to the second half of the season."
Juarez, who can play at right-back or in midfield, was snapped up by former Mexico coach Javier Aguirre for a loan deal after struggling to maintain a slot in Lennon's first-team squad.
Aguirre led Zaragoza to 13th place in La Liga last season, but was sacked in December after a disappointing start to the 2011-12 campaign.