There was a time when Doc Rivers couldn’t tell the difference between Jason Collins and his twin brother Jarron. After a brief partnership that clearly left a mark on the Celtics’ head coach, that case of mistaken identity probably won’t be made again.

Jason Collins was back in town for the first time since getting dealt to the Washington Wizards, along with Leandro Barbosa, in the deadline deal that brought Jordan Crawford to Boston. Collins wasn’t going to be mistaken for Bill Russell, or even P.J. Brown and Kendrick Perkins for that matter, but his impact was felt in the locker room during the first half of this season.

“He’s one of the best guys I’ve ever had in the locker room, player or coach,” Rivers said before the Celtics took on the Wizards at the Garden. “He’s just good. He’s a good guy and what he says is the truth. . . . He’s honest with the coaching staff and he’s honest with players. A player will complain about something and he will tell him the truth, and a lot of guys don’t want to hear the truth.”

It was Collins old school approach that had him meshing with both young and old on and off the court, and he received a warm welcome from his former teammates in green, including getting bull-rushed by Celtics forward Jeff Green at midcourt during pregame warm-ups.

“He showed me how to be a true professional,” Green said. “He always came to work ready to work and did what he had to do. He worked hard and he was a good guy. You don’t find too many of those guys.”

A quick look at the numbers and Collins could be thought of as throwaway production. He only averaged 1.2 points per game and 1.6 rebounds a night, while averaging a shade over 10 minutes in the first four-plus months of the season.

But with the way that the Celtics have been decimated along the frontline, with Kevin Garnett missing eight straight games and the combination of Green and Brandon Bass seeing more of the lion’s share at the center position, the thought of having a living, breathing 7-footer on the roster would be a welcome sight as the Celtics have given up 13.0 offensive rebounds per game in the eight contests Garnett missed.

“It’s the business of basketball,” Collins said. “It goes with the sport and with being in the NBA. Decisions are made that you might not agree with, but you just have to be professional and move on with your career.”