The number of known coronavirus cases within the NBA doubled to 14 on Thursday, when Marcus Smart of the Boston Celtics pleaded with people to take social distancing more seriously and the league ordered all teams to shutter their training facilities indefinitely.

Smart revealed that he tested positive and the Los Angeles Lakers said two of their players tested positive as well, bringing the number of players who have acquired the virus to 10. The Philadelphia 76ers said three members of their organization tested positive and the Denver Nuggets said someone within their franchise was positive as well.

The 76ers and Nuggets did not say if the affected people were players, coaches or other staff.

“I’ve had no symptoms and I feel great,” Smart said on Twitter. “But the younger generation in our country MUST self distance. This is not a joke. Not doing so is selfish. Together we can beat this, but we must beat it together by being apart for a short while.”

The league wants its teams to keep distance as well. Earlier Thursday, the NBA sent a memo to teams telling them to close their training and practice facilities to all players and staff — plus recommending that players “take aggressive measures to avoid contact with others and remain home as much as possible, leaving only for essential activities.”