The news release announcing the former Georgetown and NBA star's absence Thursday did not offer any other details or explanation.
Georgetown said assistant Louis Orr will serve as the team's acting coach "starting with the Butler game."
That is supposed to be the second game for Georgetown since it had four in a row postponed because of the COVID-19 pandemic.
Ewing, 59, was hospitalized in May 2020 after testing positive for COVID-19.
The Hoyas' next scheduled outing is Sunday against St. John's at Madison Square Garden, where Ewing played for the New York Knicks after his college career at Georgetown.
As a player, the 7-footer helped Georgetown win the 1984 NCAA championship and reach two other title games. He was taken with the No. 1 overall pick in the 1985 draft after the Knicks won the NBA's first lottery. Ewing wound up leading New York to the 1994 NBA Finals, where they lost to Hakeem Olajuwon and the Houston Rockets.
In April 2017, he returned to Georgetown for his first job as a head coach at any level, hiring Orr as one of his assistants. Orr previously was a head coach at Siena, Seton Hall and Bowling Green.
Georgetown is 6-6 overall and 0-1 in the Big East. Butler is 8-6 overall and 1-2 in conference play.