Jenas believes Van de Beek is impaired by fear and the constant comparisons with Fernandes.
United forked out a mammoth €39 million to secure the services of Van de Beek before the beginning of this season.
Having established himself as one of the best performers in the Eredivisie in previous seasons, expectations around the Dutchman were high but that has not been the case.
Although he has featured in 25 games this season, Van de Beek has only seven starts.
The Ajax academy graduate was given a starting berth in Manchester United’s FA Cup game against West Ham United on Tuesday but the youngster was substituted for Fernandes after another anonymous performance.
Jenas, who spoke about Van de Beek’s struggles, displayed his empathy towards the midfielder.
“That look on his face there I’ve just seen sums up unfortunately the way he’s playing at the moment, with a bit of fear and a lack of rhythm. I honestly don’t think it’s his fault. He’s out there being professional, doing everything he possibly can,” Jenas said on BBC Sport.
“It’s a bit better from Donny van de Beek but it still feels like everything is taking a bit too long. You have to be careful not to try and think Van de Beek can do what Bruno Fernandes can do. He’s his own type of player.”
He added: “When you don’t have that run of games in your system or belief that you can go out there and afford to make mistakes, you don’t show the full version of who you are, and that creative streak which got him to the football club in the first place.
“I think Van de Beek is still working out of what he is for Manchester United. I’d still like him to want the ball a bit more. Maybe have a shot instead of passing it back or passing it sideways. This United do not look for him, which is a bit of an issue.”
