The 24-year-old left-back was released by Villa this summer but impressed on loan at Doncaster last season.
Pompey first-team coach Ian Foster told the News: “There are a number of players we are looking it but we are aware of Enda.
“Unfortunately it hasn’t worked out for him at Aston Villa but he will find a level in England I’m sure and will make a good career.
“I’ve seen him play in League One and he’s very, very comfortable, plus he is getting that Football League experience.
“I think at Enda’s age he probably now just needs to play.”