BOSTON (CBS) — The Celtics still had a chance to avoid the play-in tournament with a win over the Miami Heat on Tuesday night. That chance is all but gone now after yet another disappointing defeat.

The Celtics dropped their third straight overall and second straight to the Heat, 129-121, on their home floor and essentially sealed their fate as a play-in team. Boston will now have to play a game or two just to qualify for the real playoffs, something the team has been trying to avoid for weeks.

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Alas, they keep squandering any chance they have at jumping to the six-seed in the East. There remains a slight glimmer of hope that they can avoid the play-in tournament, but Boston would have to win its remaining three games and the New York Knicks would have to lose their remaining three games.

Fittingly, the two teams will square off Sunday afternoon on the final day of the regular season. Before that tilt, Boston plays the Cavaliers in Cleveland on Wednesday and the Timberwolves in Minnesota on Saturday. The Knicks host the San Antonio Spurs and Charlotte Hornets before welcoming the Celtics to Madison Square Garden on Sunday.

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A Celtics loss or a Knicks win ahead of Sunday’s game will officially put Boston into the play-in tournament. Boston is currently two games ahead of Charlotte for the seven-seed, and would host the Hornets in the first play-in game if the standings remain as they are.

It’s not a a great reality for a Celtics team that is without All-Star Jaylen Brown the rest of the season, but it’s the bed that Boston has made itself with a 35-34 campaign thus far.

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“We just want to try to finish as strong as we can and see how everything plays out and just take it game by game,” Kemba Walker said after Tuesday’s loss. “That’s all you can do. You can’t sit back and complain or anything like that. You try to continue to get better, try to push forward, try to stay together as a team, which is on myself and a few other guys as well.”