Leto did not meet Hefner at the event as he was not feeling well.
But Ratner feels "there's enough footage on Hef out there that Jared will be able to get as much information as he wants", he said.
Hefner starred on many TV shows, including Entourage and Sex And The City.
Meanwhile, details have emerged that Hefner died of cardiac arrest and respiratory failure.
His death certificate revealed he was battling E. coli and blood poisoning for six days before dying.
The document obtained by New York Post explains that Hefner's infection was "highly resistant to antibiotics".
Hefner passed away in his famed mansion in Los Angeles on September 27. He was laid to rest in a private memorial last weekend.
On Monday, Hefner's wife Crystal made her first statement since his passing. She told People magazine: "I am heartbroken. I am still in disbelief.
"He gave me life. He gave me direction. He taught me kindness.
"I will feel eternally grateful to have been by his side, holding his hand, and telling him how much I love him.
"He changed my life, he saved my life. He made me feel loved every single day."