Duran saw moves to Chelsea and West Ham United fall through over the summer. He also upset Villa support by touting himself to West Ham on social media after making the club's famous cross sign.
However, with the market now shut, Duran has shone in Villa's attack and won praise from both manager Unai Emery and skipper John McGinn in recent days.
Asked about the Colombian's situation, Heskey told Tribal Football: “He's a great hold-up player, a more traditional number nine for Villa to play the ball into and he can bring other players into the game through his strong link-up play, and he can finish.
"For some managers, they have decisions to make and it's horses for courses, isn't it?
“Sometimes you need someone like Jhon Duran to relieve pressure and hold the ball up, but then sometimes you need someone like Watkins to run in behind and cause problems. More often than not, Villa will need and pick Ollie, but Duran is technically very good.
“He is definitely second choice for now but at some stage, he's got to stake a claim to try and be the outright striker. Competition for places is very good for Villa, but I would advise Duran to try and stand out now.”
Meanwhile, Heskey isn't surprised to see Amadou Onana hit the ground running at Villa. The Belgium midfielder has struck twice in three Premier League games since his summer arrival from Everton.
“I think Amadou Onana is a fantastic signing for Villa," continued Heskey.
"I mean no disrespect to Everton but it’s difficult to look good and be outstanding in that team, which he really managed to do at times.
“However, now he's showing his full ability and talents in a technically better team like we have seen him do with Belgium. Villa looked at him and thought, he fits our profile, style, he can get up and down the pitch, he's six foot five and can play.
“In years to come, he will prove that he was a bargain because he's already stepping up to the plate, so it’s a great signing.”
