The team announced no players tested positive for the virus.
The Phillies have canceled Thursday's workouts after two staff members tested positive for COVID-19.
The two positive tests came from Wednesday's round of testing. The team said no players tested positive for the virus but one coach and one home clubhouse staff member did.
"All activity at Citizens Bank Park has been canceled today and until further notice," the Phillies said in a statement.
The decision comes amid a disastrous week in Major League Baseball where over a dozen Marlins players tested positive for COVID-19 following their weekend series in Philadelphia. The Phillies have been in isolation since then and were scheduled to resume play on Saturday with a doubleheader against the Blue Jays.
MLB has run into a slate of scheduling issues this week. The Yankees had a pair of games against Philadelphia postponed due to the positive COVID-19 tests and instead traveled to Baltimore for a two-day series on Wednesday and Thursday. The Orioles previously were scheduled to play the Marlins.
In response to MLB's scheduling chaos, the MLB Players Association reportedly asked players to consider a rules change regarding doubleheaders in 2020. The MLBPA's proposal would include either one 9-inning and one 7-inning game in a doubleheader, or alternatively a pair of 7-inning games. There could also be an extension for the period in which teams use the current 30-man roster, which was supposed to decline to 28 players after two weeks and then to 26 men two weeks after that.