The fullback is a target for Everton manager Roberto Martinez.
"It's a compliment if anything if someone like Roberto Martinez comes to watch some of our young players," McNamara told Sky Sports News. "There is a lot of speculation at the moment, which we are just having to get used to.
"We have had no bids for any of our players. We have had a couple of phone calls and some enquiries but that's as far as it has gone.
"Andrew just joined us last summer. He is only 19-years-old and has just had six months with us. I think how he's done since he has joined us has been fantastic.
"I genuinely think the best thing would be for him to stay with us at least until the summer and continue to learn and enjoy his football.
"I speak to all the young lads about the speculation and when a bid comes in I will inform them of that. At the moment, I am trying to get them focused on winning matches for Dundee United."