But he insists he is keen to keep the defender at Tynecastle and claims there has been no direct contact from the Molineux outfit.
Frail told the Evening News: "I know Mick McCarthy was at the game against Rangers but whether he was there to watch Christophe or not, I don't know.
"When our players are doing well, there's obviously going to be interest in them. I think it's just a sign that your players are doing their jobs.
"He's done well recently and we wouldn't want to lose him."
