Cuellar initially left Ibrox to join Villa in 2008 and he has made over 100 appearances during his time with the Premier League club.
However, his future at Villa Park is uncertain following former Gers boss Alex McLeish's appointment as manager and an offer of ?1.5million has already been rejected.
Reports suggest Villa want double that amount to sanction Cuellar's sale, but McCoist doubts Rangers will offer that sum for the Spaniard.
"Gordon Smith (director of football) has been talking to Aston Villa about Carlos," said McCoist in the Daily Record.
"I'm very keen for that deal to go through, but I don't think we'd be going as far as ?3million to make it happen."
Christophe Berra has been mooted as an alternative option to Cuellar, but McCoist says Gers will not be following up an interest in Wolves' former Hearts centre-half.
The Rangers boss added: "He was a player we looked at but won't be pursuing."
Source: Team Talk
Source: Team Talk