Anderson in for Martin on 'Law & Order'

In 18 seasons, "Law & Order" has cycled through a couple dozen actors in lead roles. So the latest change is just business as usual.

But Jesse L. Martin's last episode as one of the show's stars coincides with Anthony Anderson's first episode as one of the show's stars. And that is something out of the ordinary.

"It was really kismet," said Dick Wolf, creator/executive producer of "Law & Order." "I don't think that there was a plan that we were going to do the overlap."

Generally, when a character leaves there's a brief mention after his or her departure.

"This was just an opportunity after 19 years to do something different," Wolf said.

There was plenty of time to plan for it. It's not like Martin is being kicked off the show. He asked out of his contract, and Wolf let Martin go before he had to.

"This is something we've been discussing for about the last six, seven months," Wolf said. "He had made it very clear a year ago that he was feeling kind of burned out. He was going into his ninth season and he (wanted) the option of leaving.

"And I don't feel that — especially when people have done the type of work that Jesse has done — that you keep them under a ball and chain even though we had a deal with him this year."

Then Anderson's Fox show, "K-ville," was canceled, making him available for "Law & Order." He signed on during the writers' strike, and once the strike ended, his entrance and Martin's exit were orchestrated.

Like many of the show's stars before him, Martin found it tough to continue playing a character on a show that isn't about character development, it's about the crimes. Wolf acknowledged that but repeated what he's been telling TV critics for years:

"We do not dole out (personal) information with soup ladles. We do it with eyedroppers," he said. "But if you're a regular viewer of the show, you do know an enormous amount of substantive information about the characters. But you've got to pay attention."

No matter how closely you've watched over the past nine seasons, you're still in for some surprises about Martin's character, detective Ed Green.