Former Derby County forward Paul Dickov has advised the Rams that they must strengthen their squad before the end of the summer window if they are to avoid relegation from the Championship.
Derby was promoted from League One at the second attempt last year, finishing second in the table behind Portsmouth.
Warne’s side had won one of their first two games of the season, defeating Middlesbrough at Pride Park last weekend after losing to Blackburn Rovers on the opening day.
Derby made numerous acquisitions this summer, including Jacob Widell Zetterstrom, Kenzo Goudmijn, and Ben Osborn, among others.
Ebou Adams’ return on a permanent basis was also confirmed following his initial loan move from Cardiff City the previous season.