Curtis, 43, was arraigned Thursday at Barry County District Court on five counts of criminal sexual conduct and was released after posting $25,000 in cash on a $250,000 bond, county undersheriff Robert Baker said.
The two teenage girls are students at Lakewood High School, according to Barry County prosecutor Tom Evans, who authorized the charges. Curtis had been volunteering at the school, which is located about 50 miles southeast of Grand Rapids.
David Dodge Sr., whose firm is representing Curtis, said that Curtis "denies any criminal wrongdoing," and added that he couldn't say anything else about the pending case.
The former outfielder played with six teams -- the Angels, Yankees, Rangers, Tigers, Dodgers and Indians -- over 10 Major League seasons from 1992-2001. He finished his career as a .264 hitter with 101 homers and 461 RBIs.