In 2007, Celtics co-owner Wyc Grousbeck was sequestered in a conference room at the NBA’s television studios in Secaucus, N.J., as the draft lottery ping-pong balls danced and revealed which teams would receive the top three picks.

As is custom, Grousbeck and the representatives from other teams had relinquished their cellphones so they could not relay the results to the outside world prior to the national television broadcast. But during the show, before the big reveal, there was a brief shot inside that locked-down lottery room. And back in Boston, other Celtics executives needed just that flash of Grousbeck’s face to know that it had not been a good night.

Sure enough, the Celtics, who entered the lottery with the second-best chance of securing the No. 1 overall pick, ended up with the fifth choice, the worst possible outcome.

After that frustrating day, Grousbeck vowed that he would never be the team’s in-the-lottery-room rep again. But on Tuesday night, as the Celtics await the fate of the pick they are receiving from the Brooklyn Nets, that is exactly where Grousbeck will be once again.

So, what changed? Well, Grousbeck stepped back and realized that in a roundabout way, 2007 was not so unlucky after all. Boston used that No. 5 pick as a main chip to acquire Ray Allen from the Sonics, and that made it easier to acquire Kevin Garnett, and that led to the 2008 NBA title.

“We pinned a lot of hopes on that lottery pick, and we didn’t win the lottery, but we did win the league,’’ Grousbeck said, “because Danny [Ainge] was able to turn the pieces we had into a great team.’’

When Grousbeck enters the lottery room this year, he said, his talisman will be his NBA championship ring. Out on the main stage, All-Star point guard Isaiah Thomas will be Boston’s representative in front of the television cameras.

Thomas said in a text message Monday that he did not plan to bring a good-luck charm, but that he would wear a green tie and green underwear.

“So hopefully that gives me good luck,’’ Thomas said. “Me being there will be all the luck we need.’’

This season, the Nets pick swelled into something of an obsession for many Celtics fans, as they tracked Brooklyn’s results almost as closely as they tracked Boston’s. When the Nets lost the first seven games of the season, it ignited the possibility that they could finish with the worst record in the league.

Instead, the Nets finished with the third-worst record, which still sets up the Celtics quite nicely. There is a 15.6 percent chance that the lottery pick will be No. 1 overall, and a 46.9 percent chance that it will fall in the top three. The No. 5 pick is actually the most likely outcome, at 26.5 percent, and the selection can be no worse than sixth.

“I don’t think we’re putting everything on this pick, because we have other ways to improve,’’ Grousbeck said. “We’ve got a lot of draft picks and we’ve got free agency and we’ve got a lot of young players. I guess I don’t feel like we’re pinning all of our hopes on the Brooklyn pick. It’s just one piece of the puzzle.’’

The Celtics hold a total of eight picks in next month’s draft, including the 16th and 23d overall choices. The team is obviously eager to find out where the lottery pick will fall, partly so it can narrow its focus and partly so it can more actively explore potential trades.

“Once the ping-pong balls fall, I think there will at least be a little bit of a more clear path,’’ Ainge said, “and more certainty in talks and conversations with other teams.’’

The Celtics have many options to upgrade their roster as they approach what figures to be a busy offseason, and Grousbeck hopes that a favorable result Tuesday will give them an early boost into the summer.

“If any of our three first-round picks could be useful in making things happen, they’ve got to be on the table,’’ he said. “We’re not saying we’re building for five years from now. We’re saying we’d like to build for now, and if we need to take young guys and build for three to five years from now, that’s what we’ll do.

“But there will be phone calls around the draft and free agency, and there will be opportunities to maybe sign and trade, or opportunities to just simply trade, and if that pick comes into the mix, certainly other teams will be calling about it. People will call about it, and I’m sure Danny will take their calls.’’

Adam Himmelsbach can be reached at adam.himmelsbach @globe.com. Follow him on Twitter @adamhimmelsbach.