Boston is three games up on Milwaukee with three games to play in the regular season, but the Bucks own the head-to-head tiebreaker after winning three of the four head-to-head matchups this season, which leaves the Celtics' magic number at 1. Any Boston win or Milwaukee loss would lock Boston into the seventh seed in the Eastern Conference.
The Celtics visit Orlando on Saturday night, while the Bucks travel to Charlotte.
It was a long shot in recent weeks, especially given their struggles, but now the Celtics can no longer move up in the seedings. The currently sixth-seeded Bulls own a three-game edge with three games to play for each team and also carry the head-to-head tiebreaker (conference record).
Once the seventh seed is locked in, the only thing Boston will be waiting for is confirmation it will open the playoffs in New York next weekend. The Knicks are three games up on Indiana and, barring the unforeseen, should lock up the second seed as early as Sunday when the two teams meet in New York.