BOSTON -- The Boston Celtics as an afterthought?

That seems to be the perception as the Celtics open their NBA season Wednesday at the Wells Fargo Center against the 76ers.

The thinking around the NBA is that the Eastern Conference will be decided between either the Sixers or the favored Milwaukee Bucks. It’s not just the fans’ perception. A recent NBA.com survey of general managers asked them to rank the top four teams in the Eastern Conference. Boston did finish third in those rankings.

The Celtics, while respecting the Sixers, clearly are not ready to anoint them, the Bucks or any team as the Eastern Conference champions.

“Playing against those guys over the years, it is a good team, a really good team,” said Kemba Walker, the Celtics new point guard, after practice last week about the Sixers. “They are a great group of guys, with great young talent, obviously Ben (Simmons) and (Joel) Embiid.”

After eliminating the Sixers in five games during the 2018 Eastern Conference semifinals before losing to the LeBron-led Cleveland Cavaliers in the Eastern Conference finals in seven games, Boston took a step back last season. Following a four-game sweep of the Indiana Pacers in the first round of the playoffs, the Celtics then lost in five games to the Bucks during the Eastern Conference semifinals, dropping the final four games.

Point guard Kyrie Irving, who was criticized for his leadership, not to mention his substandard play in the postseason (21.9 percent three-point shooting against Milwaukee), bolted for the Brooklyn Nets in free agency.

Now the team will be guided by Walker, who played all 82 games last season for Charlotte and was a three-time All-Star in his eight seasons with the Charlotte Hornets.

“We know it is going to be tough (Wednesday night), that environment is going to be tough as hell,” he said. “We will go in there and compete as hard as possible.”

That’s not exactly bulletin board material, which is how Boston likes it.

With Irving’s departure, this has been a relatively quiet preseason for the Celtics, who like it that way.

“This year I am learning not to pay attention to the outside noise,” said third-year forward Jayson Tatum. “Last year all everybody talked about was the Celtics. We are just trying to focus on basketball, focus on us and let our work take care of itself.”

After an outstanding rookie year that included a big playoff series against the Sixers when he averaged 23.6 points, Tatum took a step back last season.

The Celtics also must replace Al Horford, who signed with the Sixers as a free agent.

A major plus is that Boston will have a fully healthy Gordon Hayward, a sharp-shooter who suffered a gruesome broke leg in the opener of the 2017-18 season, his first with the Celtics. Last year he returned, but took time to regain his form.

This season?

“I am feeling really good, the leg feels great,” said Hayward a one-time all-star with Utah. “It’s another year to settle in Boston and ready to go this year.”

And another year to renew the Sixers rivalry against team that the Celtics clearly respect but won’t concede anything to.

“Before, people were saying they were young and inexperienced,” Hayward said of the Sixers. “Now they have been to the playoffs (two straight years), they know what they are doing so they are going to be good for sure.”