Ibrahimovic netted 28 times in all competitions for United, but a knee injury brought his campaign to an early end and he left the club at season's conclusion.
Silvestre, who won five Premier League titles at United, believes that will give Martial an opportunity after the France international struggled to back up his breakout 2015-16 campaign, during which he scored 17 goals.
"Zlatan's aura was big. So was his character, his ego, and what he was spreading around him was sometimes intimidating for the younger players," he said, via the Daily Star .
"It also gives you an example to follow, so it was good to have him around. But for the younger players and Anthony, you'd expect them to score more goals."
Silvestre also compared Martial to another Frenchman, in-demand Monaco star Kylian Mbappe.
Mbappe, 18, is linked with a move to the likes of Real Madrid and Arsenal after a stunning campaign for the Ligue 1 champions.
On Martial, Silvestre said: "Every time he touches the ball, even out here in training when it's early doors, you can sense the danger and the defenders – I wouldn't say they're afraid – but you don't dive into a challenge when you're facing Anthony.
"He can go left or right, and beat you with speed."