Colsaerts will be the only Ryder Cup rookie on the team captained by Jose Maria Olazabal.
"Nicolas, obviously, he's a rookie, but if you look at the team he's going to be the only rookie," Olazabal said. "His match play record is very good. He's had a very solid season and on top of that, he's made the extra effort trying to make the team. He really showed me he wanted to be part of that team."
The Ryder Cup, a biennial tournament pitting teams from Europe and the United States against each other, is scheduled for Sept. 28-30 at the Medinah Country Club in Illinois.
Poulter went 3-1 in helping Europe win the 2010 Ryder Cup 14 1/2-13 1/2 but the United States has claimed the competition 25 times in the 38 tournaments.
U.S. team captain Davis Love III is expected to make his final team selections next week. Already qualified for the U.S. team are Keegan Bradley, Jason Dufner, Zach Johnson, Matt Kuchar, Phil Mickelson, Webb Simpson, Bubba Watson and Tiger Woods.