In one instant, the vibe around the Hawks shifted from the possibility of contending for an Eastern Conference title to simply cobbling together enough victories to qualify for the NBA playoffs.

That's the impact of the torn left pectoral muscle suffered by Hawks All-Star center Al Horford. An MRI on Thursday confirmed the tear, and Horford said he plans to have surgery that would sideline him for three to four months.

Under the most optimistic time frame, Horford would return near the end of the regular season and be ready for playoffs. But if Horford needs the full four months to recover he essentially would be out for the playoffs.