Cuellar has linked up with Blackburn for training after leaving Sunderland earlier this summer.
The 32-year-old will spend this week training with Rovers and is expected to feature in Wednesday's pre-season friendly against Bury.
Blackburn boss Gary Bowyer is looking for defensive reinforcements and Cuellar's experience and versatility, given that he can play at centre-back and right-back, would make him an attractive proposition.
Cuellar is the second player to be in training at Blackburn this week, with former West Ham United full-back Jordan Spence also set to feature against Bury.
Cuellar first arrived in Britain in 2007 when he joined Rangers from Osasuna before moving to Aston Villa and then to Sunderland in 2012.