O'Driscoll starts his second game in five days, with Lions boss Sir Clive Woodward preparing to send out a near Test-strength side.
Umaga would have opposed O'Driscoll in a mouthwatering midfield clash, had he not been on All Blacks squad duty with his fellow Wellington-based stars Jerry Collins, Rodney So'oialo and Conrad Smith.
And while the Lions' degree of difficulty is eased by their combined absence, they must still produce a convincing display following Saturday's defeat against New Zealand Maori.
O'Driscoll will be at the heart of that effort, and Umaga has no doubt about his qualities.
"I played against him twice against Ireland," Umaga said. "He's a brilliant player and a very good man, very relaxed, and I've got a lot of time for him as a player and as a person.
"For Brian, it's not that he will be captaining (the Lions) alone. He's got so much experience there with him, and I know he will get the help required.
"It's the same with us. You cannot expect one guy to do it all or try to be the main talker, because it's just impractical with so many people on the field.
"You have to develop leaders, but they (the Lions) don't have to because they are all leaders in that side and the senior players have pretty much played for their country for a long time."