“When we made the Pierce and Garnett trade, it was having lost to the Knicks in the first round in 2013 that was the deciding factor,” Celtics co-owner Wyc Grousbeck said in a phone interview Thursday. “The fact that we lost to them was a clear indicator that we were not going anywhere with that group as constituted.

But as the years rolled on and the powerful core began to age, it became clear that there would come a time to regroup and rebuild to form another roster capable of a sustained period of title contention.

The Celtics’ run from 2007-13 that was spearheaded by Paul Pierce and Kevin Garnett included three trips to the conference finals, two appearances in the NBA Finals, and one world championship.


“They had been great. We won a championship. They were fabulous and will always be in Boston sports history, but it was time to change.”

The current Celtics, whose foundation was built by the draft picks the team acquired by trading Garnett and Pierce to the Nets, are quite different from those Celtics. They are younger. They have not reached the Finals. This feels closer to their beginning than their end.

Nevertheless, this season has been a disappointment so far. The Celtics entered the year thinking about a Finals berth, and instead are locked in a battle just to secure home-court advantage in the opening round of the playoffs. So Grousbeck said he will have an eye on his team as well as all the others in the coming months as Boston’s front office determines which road to take next.

“I think this is the time of year where you watch every possession, every game, every playoff series very closely,” Grousbeck said, “and try to decide what to do in June.”

This stretch will be an important part of the evaluation process for the future, as the Celtics look to upgrade the roster where necessary. But Grousbeck also emphasized that he has not lost hope for what is possible now.


He has been at the team’s practice facility the last two days and said the team’s vibe and energy have been good. He believes the players are focused on a playoff run.

“We’re trying to sort of finish off a rebuilding process here and get to an elite level, and we have not played at an elite level this year,” Grousbeck said. “We have to admit that at the moment. We’re in fifth place in the East.

“It’d be great to take that step now, or we’ll try to take it next year if we have to. But what I’m seeing, with the playoffs around the corner, I’m going to go into the playoffs with good energy and optimism and seeing what happens.

“I like watching this team. When we’re hitting on all cylinders, we’re a dangerous team. So I’m hopeful that we can find that place starting [Friday] night [against the Pacers].”

Recent Celtics teams have often been defined by their chemistry and intensity and their ability to play harder than their opponents on most nights. There have been issues in all of those areas this year.

Grousbeck declined to talk about why he thinks this season has not gone as planned, and he also declined to comment about the culpability, play, or future of any individual player.


Coach Brad Stevens has publicly shouldered the blame during several disconcerting stretches this season and has even faced some outside criticism for the first time in his Celtics tenure. But Grousbeck made it clear that he remains firmly in Stevens’s corner.

“Brad would be my top choice to coach the team — if we were doing a search right now, he would be the hands-down winner,” Grousbeck said. “I can’t be more impressed with Brad. He’s hung in there through ups and downs this year and he coaches basically 24/7 to an extremely high level. I’m very glad he’s a Celtic.

“The only criticism that matters comes from inside the organization, and he’s not experiencing any of that.”

Grousbeck said he was encouraged by the Celtics’ play in their win over the Cavaliers on Tuesday. But he added there have been encouraging moments in many games this year. That has yet to translate into something that lasts.

“We have talent,” Grousbeck said. “It’s a question of meshing it together and making it work for a complete game at a time, or a series of games at a time.

“I think starting [Friday] night at home against Indiana, in a really important game, I’ll be hoping to see a sustained team effort. But these aren’t throwaway games anymore. These are really important games. So it starts tomorrow night. We’re in a new phase of the season.”

And make no mistake, when this phase ends, Grousbeck and the Celtics will be ready for what’s next. They are in position to have four first-round picks in the draft. Their pursuit of Pelicans superstar Anthony Davis is well-known. The chase never stops.


“I’m going to watch the playoffs, I’m going to root hard for us to go as far as we can possibly go,” Grousbeck said, “and then we’ll all collect our thoughts in June and decide what to do next.”

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