Wolfsburg sporting director Klaus Allofs admits the Bundesliga club has failed to adequately replace Kevin De Bruyne and Ivan Perisic following the duo's departures in 2015.
De Bruyne and Perisic played a key role in Wolfsburg's second-place finish in 2014-15 and their fine performances eventually earned them transfers to Manchester City and Inter Milan respectively.
But Wolfsburg has failed to build on that strong campaign since the exits of two of its key men - finishing eighth last term, while the club sits 16th this season - and Allofs has acknowledged selling the two attacking midfielders has cost the team.