Both the England internationals are right-backs by trade, although the duo have played further up the pitch in a wing-back role.
Walker is the first-choice right-back for the England football team at the moment, while Trippier is part of the current squad but has earned just one cap for the Three Lions so far in his career.
The 27-year-old Spurs star was the deputy to the City ace at Tottenham for the past two seasons.
Walker left Tottenham to join Premier League rivals City in the summer transfer window and has started his career at the Etihad Stadium strongly.
Former Arsenal star Merson believes that both Walker and Trippier should be part of the England squad for the 2018 World Cup finals in Russia, but he seems to prefer the City star to the Spurs man.
“Walker is the best in the business at right wing-back, while Trippier is not far behind him.
“I'd like to see England play three at the back throughout the tournament, so 'traditional' full-backs aren't needed.”