Toon boss Kevin Keegan watched Cuellar in action on Thursday night against Sporting Lisbon, but the modest Spaniard said: "When a team's doing well it's normal to have interest from other clubs.
"We have done well in the league and made the quarter finals of the UEFA Cup so it's natural that English and Spanish teams are watching.
"There are a lot of good players here. But right now I'm only concentrating on Dundee United and the rest of the campaign.
"I'm focused until the end of the season - nothing else bothers me."