The England Under 21 international is a loan target for both Championship clubs ahead of the new season.
The 21 year old only joined Portsmouth last summer, but he has struggled to establish himself at Fratton Park.
Pompey boss Harry Redknapp is believed to be keen to loan out Cranie so he can get some action under his belt.
The news has alerted both Coventry boss Chris Coleman and Addicks chief Alan Pardew.