Herculez Gomez and Mark Donaldson delve into why American players find homes in the Bundesliga more so than other leagues in Europe.
Germany international Boateng lasted only 10 minutes of the game before having to be helped from the pitch with a thigh injury.
Martin Schmidt has left his job as Mainz coach by mutual consent, the Bundesliga club have announced.
U.S. forward Boyd made his Bundesliga debut after leaving RB Leipzig for Darmstadt in January.
McKennie was brought on for the final 13 minutes as a 10-man Schalke held on for a point.
Aubameyang, 27, the Bundesliga's top scorer, has been linked with Paris Saint-Germain and Chinese Super League club Tianjin Quanijan in recent weeks.