Iwobi has made three Premier League starts since moving to Goodison Park in the summer, while Richarlison has failed to find the net in his last five games across all competitions.
Both players come face to face on Sunday, when Nigeria take on Brazil in an international friendly match in Singapore.
Speaking to Football Insider, Whelan said: “He (Iwobi) was the most effective Everton player against Burnley at the weekend.
“He’s got the pace and ability to beat players and create chances, and that’s something they’re lacking at the moment.
“Richarlison looks like he has lost confidence and belief in himself, and Iwobi is a bigger threat.
“He’s a brilliant talent, he just needs to find more consistency and better decision-making. The raw skill and ability is there.
“If he starts to realise his potential, he can keep Silva in his job.”
