Duffy has been on the books of Blackburn since the summer of 2014 and has a contract with the Championship club until June 2017, according to Transfermarkt.co.uk.
Wolves are not the only club (reportedly) interested in securing the services of the Republic of Ireland centre-back in the summer transfer window, though.
According to a report in The Daily Mail last month, Glasgow giants Celtic are interested in the former Everton defender. It was reported that the Scottish Premiership champions had made an enquiry about Duffy.
Duffy scored four goals and created 14 chances in 41 Championship appearances for Blackburn during the 2015-16 season.
The former Everton defender had a pass accuracy of 62% and a shot accuracy of 31%, and won 290 headers, six dribbles and 32 tackles.
In two matches for the Republic of Ireland at the 2016 European Championship in France this summer, Duffy had a pass accuracy of 54%, and won 16 headers, one dribble and two tackles.