The Whites went into deadline day chasing another attacker, but were forced to settle for teenager Willy Gnonto, who arrived on a loan deal from FC Zurich.
Gelhardt has been handed minutes in recent games and the burden could fall upon him up front given Patrick Bamford has regularly suffered from niggling injuries.
The Leeds youngster is highly rated and has insisted he feels no pressure at the weight of expectation on his shoulders.
Prutton thinks that Gelhardt must take the opportunity between now and the opening of the January transfer window to nail down his spot in the team if given a chance by boss Jesse Marsch.
The former Whites midfielder told the Yorkshire Evening Post: “He could be huge. As long as he gets his games, as long as he is playing in the right position and as long as he is not a bit-part player off the bench and manages to get the starts in that is.
“This is a chance for him and there is a challenge now that lies ahead.
“There’s been lots of clamour for him but I don’t think he has had the minutes nor the impact possibly consistently regards to the fact that he hasn’t had the minutes that has warranted that first-team berth.
“If he does get that chance then now is the time to nail it down.”
Gelhardt played 59 minutes in Leeds’ 5-2 loss at Brentford in their last Premier League outing.
