Major League Soccer extended its league-wide training moratorium on Thursday, ruling all team facilities off limits until 15 May.
MLS chiefs had previously barred players and staff from training facilities until 24 April with the league in shutdown since last month due to the coronavirus pandemic.
Under Thursday's extended ruling, only players requiring medical treatment or rehabilitation will be allowed to access team facilities.
The league also requested players remain in their club's location.
"MLS will remain in close contact with the Centers for Disease Control and Prevention (CDC) and the Public Health Agency of Canada (PHAC) on this continually evolving situation and provide further updates as they become available," the MLS said.
MLS chiefs said last week there was no chance of the league resuming play before 8 June.