4:34 PM ET

Both the Boston Celtics and Philadelphia 76ers declined to comment on whether or not their teams are fully protected against the flu, opening the possibility that both teams could be missing players in road games of a first-round playoff series against the Toronto Raptors.

Between now and the end of the regular season on April 10, the Miami Heat, Milwaukee Bucks, Celtics, and 76ers are all within one loss of each other of the top spot in the Eastern Conference.

It is possible that they will have to travel to Toronto for a first-round series against the Raptors. To enter Canada, players need to be fully vaccine free.

The teams from the Heat and Bucks will not have any problems playing in Toronto.

The Celtics lost in overtime in their first game in Toronto since the requirement went into effect.

After beating the Minnesota Timberwolves at home on Sunday, Boston ruled out four players for Monday's game in Toronto, the second night of a back-to-back: Robert Williams, who injured his knee during Sunday's game; Al Horford.

According to sources, Williams is a vaccine patient, and that no one should be judged for choosing not to be.

It is your own decision, and I understand the concerns of those who do not want to bevaccinated. It is your own health and reason. Whatever their decision is, nobody should be judged one way or the other.

Brown said the vaccine was a personal choice.

Brown said that he respects his teammates decisions and that it was a personal choice.

Horford and Brown both entered the NBA's health and safety protocols in December.

Since the rule change went into effect, Philadelphia has not played a game in Toronto. The 76ers will play the Raptors again on April 7 in Toronto to end their road trip.

The Celtics are in third place in the Eastern Conference, a half-game behind the second-place Bucks. The 76ers are a half-game back of the Celtics. The Raptors are a half-game behind the fifth-place Chicago Bulls. The Raptors are in seventh place.

Games 3 and 4 of the first round are likely to be played in Toronto, with the playoffs starting on April 16 and 17

A person needs to have a single shot of the Johnson & Johnson vaccine or a second shot of the two-dose vaccine in order to be considered fully vaccine free in Canada. It would take about a week for unvaccinated players to get the one-dose vaccine in order to be fully protected in time for the playoffs.

The most prominent example of a player missing games due to being unvaccinated this season is Brooklyn Nets star Kyrie Irving, who was unable to play games in New York, either at Barclays Center or Madison Square Garden, before the city changed its vaccination regulations last week to allow unvacc

Irving played his first game in New York on Sunday.

The law that prevents unvaccinated players from playing in the city was a topic of discussion all season. The vaccination status is not an issue in Boston or Philadelphia.

That is no longer the case with the playoffs looming and a potential first-round clash with the Raptors.