WALTHAM, Mass. (AP) In any sport, the one thing a team can't prepare for is the unknown.
Last week, the Celtics were the toast of the East after outlasting the champion Cleveland Cavaliers for the top seed and home-court advantage. Then, the day before Boston's playoff opener, Isaiah Thomas' sister was killed in a car accident.
It's created a delicate balancing act. This is a team that expected to be riding a big wave of momentum.
Instead, Boston lost 106-102 to Chicago in Game 1, and the possibility looms Tuesday of falling into an 0-2 deficit.
But if there's a group built for such a challenge, it would seem to be this one. There's empathy in the locker room, and a coach adept at navigating rough situations.
''I think the biggest thing is they really care about each other,'' coach Brad Stevens said Monday. ''It's really tough when he's sitting there and some of his family is back in Seattle. ... But I think the next extension of your family is who you're around every day, and your team. ... They care about one another and they support one another. That's what you hope you have in a team, but it's probably not always the case.''
Stevens said Thomas plans to play in Game 2 Tuesday night then head to Washington state to be with his family and help complete funeral arrangements.
Chyna Thomas died early Saturday in a one-car accident outside Tacoma. No funeral date is set, but Stevens said the Celtics plan to attend.
Thomas attended a film session and walk-through Monday, but did not speak with the media. Stevens said that after services for Thomas' sister, the star guard intends to rejoin the team Friday for Game 3 in Chicago. Stevens, however, stressed that all plans are up to Thomas.
Stevens knows firsthand of how the Celtics can embrace one of their own. Last year, he was allowed to miss a game to be at the bedside of Andrew Smith, who played for Stevens at Butler. Smith had cancer and his condition had worsened. Smith died a few days after Stevens visited.
Then there was the team's public show of unity before its preseason opener in October. The players held hands during the national anthem, the display coming at a time when NFL players, notably Colin Kaepernick, were protesting by kneeling.
One of Thomas' closest friends on the team is guard Avery Bradley. The two grew up outside Seattle and played AAU ball together. During Monday's shootaround, TV cameras captured Bradley comforting a tearful Thomas on the bench.
''Me and Isaiah have known each other since we were kids,'' Bradley said. ''So no matter what goes on we're always going have each other's back. We're always going to be there for one another. I think he knows that, and I know the same about him. We're always going support each other. ... We're a family.''
Still, there is basketball to be played. And Thomas, after an unsteady beginning, played admirably in Game 1, scoring 33 points to go with six assists and five rebounds.
Retired All-Star Kevin Garnett said he thinks Thomas will be better for having gone through this.
''I anticipate him playing even more inspired,'' he told The Associated Press. ''I look at this as this momentum carries him and the Celtics. It's going to also carry the city.''
Bradley says it's important now to pick Thomas up on and off the court.
''I feel like it's better to show with your actions than your words, especially after a loss,'' he said.
In a sense, he said, it's following the example Thomas set in Game 1.
''You can say whatever to him, but I think our actions really let him know that we care for him,'' Bradley said. ''This is a sanctuary being on the basketball court. ... As brothers that's what you're supposed to do.''
AP Sports Writer Jon Krawczynski in Minneapolis contributed to this report.
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