Championship outfit Derby sold the 31-year-old defender to Burnley in the summer of 2012, but it seems that they now want him back at the iPro Stadium.
The former Barnsley defender played in all 38 league games, but he failed to prevent Burnley from getting relegated to the Championship.
The former Wolverhampton Wanderers man created nine chances, had a pass accuracy of 77% and a shot accuracy of 25%, and won 154 headers, two dribbles and 17 tackles.
Interestingly, Shackell was linked with a move to West Yorkshire outfit Leeds United when Neil Redfearn was in charge.
Back in May, The Yorkshire Evening Post reported that Redfearn wanted to sign the former Norwich City man for the 2015-16 season.
However, the Englishman is no longer the Leeds head coach, and one suspects that the Whites are not interested in Shackell anymore.