The 24-year-old, who has been watched by Everton and Liverpool this season, told the club's official website: "You always hear about rumours and gossip, but there is nothing whatsoever happening.
"The club have really signalled their intent by giving me the armband. Simon has put his faith in me and wants me to be an integral part of the future of this club."
Howard added: "It's a massive honour to be captain of any club, but to be skipper of a side that is doing so well and consistently in the top half of the Championship is a huge thing for me. My family and I are very, very proud."