Defender Reggie Cannon and midfielders Kellyn Acosta, Sebastian Lletget and Jackson Yueill are the only holdovers from the 23-man roster for the Nations League roster.
They are being given time off ahead of preseasons with their European clubs and the start of World Cup qualifying on Sept.
Also on the preliminary roster and hoping to play their way back into the first-choice player pool are midfielders Julian Green and Cristian Roldan and forwards Paul Arriola and Gyasi Zardes.
Hoppe made a splash with Schalke 04 when he became the first American to score a Bundesliga hat trick in the 4-0 win against Hoffenheim in January.
is based in Kansas City, Kansas, for the first round and opens Group B play on July 11 against Haiti, St.
Mexico, Curacao, El Salvador and a qualifier are in Group A; Costa Rica, Jamaica, Suriname and a qualifier in Group C; and Grenada, Honduras, Panama and invited guest Qatar in Group D.