Open champion Collin Morikawa is among the US first-timers at Whistling Straits, joining Xander Schauffele, Patrick Cantlay, Harris English, Scottie Scheffler and Daniel Berger as debutants in Steve Stricker’s side.
In contrast, the Europeans have just three rookies in Shane Lowry, Ian Poulter and Bernd Wiesberger while Westwood and Sergio Garcia are making their 11th and 10th appearances respectively in the match.
“Because the Ryder Cup is so different, that's a balancing act, I suppose,” said Westwood in reply to being asked if he felt a more youthful line up could be a positive for the Americans at the Wisconsin venue.
“I think in an ideal world you'd like to filter your young players in gradually a few at a time, not necessarily bang all at once in a team as rookies. But that just happens like that every now and again.
“When I look at the United States' team I think they've got a lot of strong players. It is almost like a changing of the guard for them.”
Spieth, who shone on his debut at Gleneagles in 2014, delivered his verdict on the US rookies in reply to being asked about the experience of the likes of Westwood and Garcia in the European team.
“It's probably very helpful for them,” he said of that, “but I'm pretty excited about the idea that we've got youth and fire kind of with the guys in our locker room.”