Europe were beaten 17-11 on their last attempt to retain the trophy in the United States and, while McGinley believes it will be a tall order to do so this time around at Whistling Straits, he believes Harrington should have plenty of reason for encouragement.
Irishman Harrington - a three-time major victor and vice-captain in the last three Ryder Cups - succeeds Dane Thomas Bjorn.
McIlroy admitted he "hit a wall" at Hazeltine and was clearly not on top form at Le Golf National, so it will be interesting to see if Harrington becomes the first captain to use him more sparingly.
An announcement is expected at a press conference at the European Tour's Wentworth headquarters. "I am not as stressed about everything that goes with it". "I've actually learned a lot more as vice-captain than you do as a player". I think Thomas was blessed with the best team we've ever had in France.
"I felt it was the right time for me to go for it and when you talk to the other players I certainly have their support and when I talk to the vice captains and potential captains going forward it seemed to fit very nicely that I go and do the away match".
'I really want to be a help, I want to hopefully leave the European Tour and Ryder Cup in a better place after two years. "That's something I don't take lightly". "He's become a leader in the team room", said Harrington.
The keys to the European Ryder Cup machine have officially been handed over to Padraig Harrington.
Harrington, 47, was a Ryder Cup victor in four of his six appearances as a player while he was a vice-captain in 2014 and 2016, as well as 2018.
Paul McGinley, winning European captain in 2014, welcomed the appointment.
"I'm putting it on the line - we know when you're a successful Ryder Cup captain it's great and a losing captain - it's his fault". To be honest, if I look at all of this, I'm not the fuzzy, cuddly type either so I might be more on the Bernhard Langer-style of things.
'It does make my job easier that I feel I have the confidence of the players, ' Harrington added.
"We were always playing catch up, we were playing a great team, so you learn a lot in adversity". "You just have to know the man behind the scenes".
"So yes, I think Steve will be a nice Ryder Cup captain". I know it's an uphill struggle to beat the U.S.in the USA but these are good golf courses.