The Ivory Coast international has reportedly indicated that he wants to quit Selhurst Park this summer after another standout season last time out.
Zaha chipped in with nine goals and three assists in a season disrupted by injury, leading to rumoured interest from a number of the Premier League's elite clubs.
After playing and scoring in Palace's 3-1 pre-season win against Oxford United on Saturday afternoon, Schlupp admitted that Zaha is far too important for the Eagles to lose.
"Wilf is Wilf, and he's got the X-Factor," he told Sky Sports News. "He's irreplaceable. Every time he goes out on the pitch, he does his bit and it's great to have him in the team.
"He just wants to play football and get on the pitch and show everyone what he can do. He does that pretty much every time he's out there."