The 24-year-old defender moved to Wednesday from Championship rivals Leeds United in the summer of 2014.
The former England Under-21 established himself as one of the best players for the Owls last season and has attracted interest from a number of clubs.
Carvalhal, though, has insisted that the 24-year-old will remain at Hillsborough for the 2015-16 campaign.
“We want Tom Lees," Carvalhal told The Star. “To us, he is a very, very important player. I expect everything to be clear in the next few days and he will stay with us.
“But it is not really a question of being clear because our chairman has said that we do not want to sell any of our players.”
Lees is one of the best players in the current Wednesday squad, and retaining his services will enhance the Owls’ chances of a top-six finish in the Championship next season.
The former Leeds defender created 10 chances in 44 Championship appearances during the 2014-15 campaign.
Lees had a pass accuracy of 69% and a shot accuracy of 50%, and won 196 headers, nine dribbles and 36 tackles.