The 30-year-old midfielder has been tasked with the duty of leading the Reds in recent weeks after Henderson suffered a knee injury in the Europa League quarter-final first leg away to Borussia Dortmund.
The England international is not expected to be fit in time for Liverpool's Europa League final against Sevilla on May 18 in Basle, with Milner set to lead his team-mates into the biggest battle of Jurgen Klopp's short reign in charge so far.
The former Manchester City man has captained the Merseysiders in their subsequent three European outings since his colleague's injury - two victories, one defeat - but Milner was unequivocal in his assertion that Henderson will lift the trophy, should they win it.
"Hendo will lift it if we win it,' said Milner via The Mail. "Even if he's not in the 18, he will lift the cup. He's the captain and a top player, and I have so much respect for him.
"It's been a great honour for me to have captained Liverpool and I try to do it to the best of my ability. But I don't like doing it because it means Hendo is injured."
It was former manager Brendan Rodgers' decision to name Milner - a Bosman signing from Manchester City - as vice captain, which might have raised a few eyebrows given he had only arrived, but it looks to have been a wise move by the Northern Irishman, who was sacked in October.