"He’s got the run on him and he’s got the height on him as well… he’s not aggressive enough."
Sarr has only featured five times this season with three of his appearances coming in the Carabao Cup.
Chelsea will loan Zappacosta, Sarr and Bakayoko to the Serie A before the transfer window closes.
The 19-year-old has spent the last year on loan in the Primeira Liga with FC Porto...
The 21-year-old was available as a free agent as he left Nice at the end of last season.
David Ornstein has now confirmed that Chelsea are closing in on their third signing of the summer.