Hillary Clinton's campaign is having trouble finding an individual who can effectively mimic her Republican opponent as she prepares for the upcoming presidential debates, according to Campaign Manager Robby Mook.

"It's very hard to find someone to mimic the reckless temperament and the hateful instincts and divisive instincts of Donald Trump," Mook told CNN's Dana Bash on Sunday.

"Preparing for a debate with him is a challenging task, but Secretary Clinton is looking forward to the debate," Mook added. He suggested the debates will give Americans an opportunity to see how Clinton's "steady leadership" compares with Trump's "very reckless temperament."

In the months leading up to the debates, each presidential campaign traditionally hires an experienced politician to play their candidate's opponent so he or she can better prepare for the arguments and attacks they will likely face on the real debate stage. Ohio Sen. Rob Portman was the "sparring partner" for both Mitt Romney and John McCain in 2008 and 2012, standing in for senator and then President Obama.

While the Clinton campaign continues its search for the perfect person to play Trump, Mook said he's confident the right individual will come along.

"We'll get it done," he said, adding that he and the rest of the Democratic presidential hopeful's team are "looking forward to the debates."