The Celtics’ little big man got lost in the game.

Imagine having to go to work in a high profile job, with millions of people watching you, after enduring the tragedy and personal pain of, say, Isaiah Thomas in the opening game of the NBA playoffs.

There may not be another line of work that couldn’t wait at least a day or two for Thomas to overcome the grief of losing his kid sister in a car crash the day before the playoffs began. Sure, Thomas did not have to go against the Chicago Bulls, but this is what his team and teammates have worked for the entire 82-game regular season.

Boston was the surprise winner of the Eastern Conference, beating out defending NBA champion Cleveland by two full games. As the No. 1 seed, the Celtics faced eighth-seeded Chicago in the best of seven series on their home court. Thomas, the team’s leading scorer and at 5-foot-9 the NBA’s mightiest mite, could not let a franchise, a city and himself down by running home to Seattle.

Nothing could bring 22-year-old Chyna Thomas back, and leaving his team on the biggest day of the season so far just would have compounded his pain. So Thomas played, scoring 13 points in the first quarter and finishing with a game-high 33. He got lost in the action, playing through his grief and very likely found relief for the two hours he was out there between the lines.

His coach Brad Stevens gave Thomas the option of playing or missing the first game or two of the playoffs to be with his family. They had been through something like this four years ago, when Thomas lost his 46-year-old mother. But the timing now could not have been worse. The player known as “IT” decided to play, and it was his team that let him down as listless and getting out rebounded by the Bulls on the way to a 106-102 shocker.

Thomas will play again tonight in game two and over the weekend when the series moves to Chicago. His heart will be heavy but he will get lost in the games, and maybe the memory of Lil Sis written on his sneakers will again carry him through his grief.

Let’s hope so.