Cruzeiro midfielder Everton Ribeiro has told ESPN Brasil that he would fit into the Manchester United side.
Portsmouth have named Richie Barker as their new manager and Steve Coppell as director of football.
The 25-year-old has been drafted in by Mark Robins as cover for regular left-back Blair Adams, who suffered an injury in Saturday's 1-0 home defeat to Yeovil.
Dickinson has made 44 appearances for the Hornets since joining from Stoke in the summer of 2011, but he has found first-team chances hard to come by by this season.
He has been restricted to only six appearances under Gianfranco Zola, and has not played a senior fixture since November.
Dickinson spent a month on loan with Portsmouth early this season, and he will now be with League One Coventry until 12 March.