There are – no doubt – Celtics fans wondering the following: How good would Kenyon Martin look playing alongside Kevin Garnett and Paul Pierce right about now?

But that didn’t happen, and to make matters worse, Martin is playing for a team that is threatening to run away from the Celtics in the Atlantic Division after Boston’s four-game losing streak has dropped them 6.5 games behind the Knicks entering Tuesday’s showdown at the Garden.

Doc Rivers acknowledged before Monday’s practice that Martin was on the Celtics’ radar but it never worked out. One reason, according to Rivers, it didn’t work out was the area of immediate need didn’t match. The Celtics had just lost Rajon Rondo and Leandro Barbosa to season-ending injuries. The Celtics were looking to build depth in the back-court.

“I don’t know,” Rivers said when asked why Martin didn’t wind up with the Celtics. “We looked at all the guys, we were still looking at guards at the time. So we were in no hurry at the time for a big. We were looking for more a big of size, if you know what I mean. And by the time we got around to it, he was gone.”

With injuries to Carmelo Anthony, Tyson Chandler and Amar’e Stoudemire, the Knicks were more desperate and willing to take a chance on Martin. It’s worked out quite well for New York. Martin is averaging 8.6 points, 5.3 rebounds and 23.1 minutes per game, starting six of the 11 games.

“I think Kenyon’s been great,” Rivers said of the former All-American out of Cincinnati. “He’s been absolutely fantastic. I’m happy for Kenyon. I’m not happy that he went to the Knicks, but I am happy for him. Because he was out there and we looked at him — a lot of [teams] looked at him — and, in the end, I didn’t care where he ended up, I just wanted him to do well. I don’t know him well, but we’ve always had a very good relationship. Guys like that, you want them to do well. For me, it’s as simple as that.”