The 29-year-old has not been a regular at Wolves since the club earned promotion to the Premier League during the 2008/09 season.
Wolves boss Mick McCarthy told the club’s official website: “Hilly has been a great professional during his time here with us.
“He came in and made an important contribution during the promotion-winning season and has always been a very good influence around the place.
“We would like to thank him for his efforts and wish him all the best for the future.”
