Bass, Wilcox, Green and Terry all trekked to the Celtics' practice facility Saturday to be introduced alongside Celtics president of basketball operations Danny Ainge and team owner Steve Pagliuca.
The Celtics have handshake agreements in place with Green and Terry, but there are minor details to be worked out with both before those contracts can be finalized. Green's agent, David Falk, said he expected a deal to be completed early next week.
Terry's situation is slightly more complicated.
After Ray Allen signed with the Miami Heat this week, the Celtics have increased their efforts to add a frontline shooting guard with the goal of strengthening their roster, particularly with starting shooting guard Avery Bradley undergoing a second shoulder surgery this week that leaves his status uncertain for the start of the 2012-13 campaign.
The Celtics enticed Terry to Boston with the potential for a three-year deal at the full value of the taxpayer's mid-level exception ($5 million), but have explored sign-and-trade potential with the Dallas Mavericks that would free that chip to use on another player. Without that, Boston has only the biannual exception ($1.975 million) with which to lure an outside free agent over a minimum contract.
Boston could offer Dallas a combination of contracts and draft picks in hopes of enticing the Mavericks to facilitate a sign-and-trade, but Boston doesn't have many desirable trade assets and even its future draft picks would be late-round selections if it maintains its recent success.
Sources with knowledge of the discussions told ESPN.com's Marc Stein the Mavericks and Celtics did discuss sign-and-trade scenarios to facilitate Terry's move to Boston early in free agency. But Dallas has since made other plans with its cap space, such as Friday's amnesty claim on Elton Brand, and are thus resistant to taking back Keyon Dooling or Sasha Pavlovic in a sign-and-trade, which would be necessary to make such a deal work.
A source said the only way a sign-and-trade could occur is if Boston finds a third team to take on the salaries they prefer to move out.
The Celtics have eyed unrestricted free agents such as Courtney Lee (who met with coach Doc Rivers last week in Orlando) and O.J. Mayo (who reportedly was nearly traded to Boston in exchange for Allen at the trade deadline last season).
While all that is being worked out, the Celtics still brought Terry to Boston to be formally introduced after the team put on a full-court press at the start of free agency.
"I'm still smiling from the phone call I got from Doc. He was the first one to call me," Terry said. "I'm just excited about being a part of the Celtics organization, the franchise.
"Obviously the heritage, the tradition -- by just putting the jersey on. What (Garnett), Paul Pierce, and (Rajon) Rondo have done in the present, just being a part of that, and continuing to carry that on. And I think my competitive nature, my championship fire and desire to win again is what is driving me.
"I knew I was going to be a free agent this summer, and watching the playoffs and seeing that they were one game away, I automatically, in my mind, envisioned myself in a Celtics uniform, and God willing, it happened, and it will happen pretty soon. So, I'm very excited, and I'm looking forward to it."
Green, who missed all of the 2011-12 season after undergoing surgery to repair an aortic aneurysm detected before the start of the the year, said he has unfinished business, particularly after watching the team come one win shy of the NBA Finals.
"I had big hopes last year, prior to the season starting. But unfortunately I had a minor setback," Green said. "But, yeah, I feel like I have unfinished business. I worked hard to get in the shape I was in and put my game at the level it was at in order to help the team get that extra win to make it to the championship round. I'm looking forward to next year and hopefully I can bring that energy and my skill level to help this team make it to the finals and help them win."
Bass opted out of the final year of his deal to seek long-term security and was rewarded with a three-year pact.
"I had other offers out, but I knew where I wanted to be, and that's back in the green jersey, playing for the Celtics," Bass said. "They're a great organization and it's a great group of guys who are all about winning. I'm excited to be back."
Like Green, Wilcox had his 2011-12 season ended by a heart ailment. An enlarged aorta was detected in March and he underwent surgery soon after to repair the issue. Wilcox last week resumed basketball activities and, after signing a one-year deal, said he expects to be ready for the start of training camp.
"This is a blessing. This is a blessing for me to even be here right now," Wilcox said. "I'm just going to take full advantage of all my situations and all the opportunities that's been coming to my way, and, like I said, it's a blessing that I'm able to come back to a team to kind of pick up where I left off."
Not surprisingly, the notoriously private Garnett did not make the trip back to Boston to be part of the festivities despite inking a three-year extension.
Ainge acknowledged Garnett was the team's No. 1 priority this offseason.
"I guess we're glossing over it just because he's not here and because we've known it for a couple weeks now, but that was a priority for us this summer, just to get KG back," Ainge said. "That was a great relief to get him back. He's such a big part of who we are and going forward, we think he has a lot of basketball left in him."