"I'm not sure if this is the last season; it may be, and all good things come to an end. It will be bittersweet," he told reporters Tuesday.
The sixth season of "The Sopranos," which Imperioli begins filming April 29, is expected to be its last — unless, of course, Chase changes his mind.
"Nothing official has been said [about this being the final season] — David Chase said the same thing about the fifth season [being the final season]," Imperioli said.
"I heard a month ago that we were doing a seventh season, and then I heard we're not doing a seventh season," he said.
"The last time I saw David, he was on the fence [about a seventh season]."
Imperioli, who begins a four-episode storyline as good-guy Det. Nick Falco on "Law & Order" (search) April 27, downplayed the long hiatus between seasons of "The Sopranos."
The show's fifth-season finale aired last June, and the sixth season won't bow until early next year.
"I'm looking forward to getting back to work," Imperioli said. "It's a luxury to have a secure thing in this business and to have so much time in between to do other things. It's about as good as it gets in the world of New York television."
Imperioli begins filming on the new "Sopranos" season four days after he wraps filming on his four-episode "L&O" storyline.
But he said he hasn't yet seen a "Sopranos" script and doesn't know what's in store for his character, Christopher Moltisanti.
Imperioli was asked what he'd like to see happen to Christopher, who's fiancee, Adriana, was whacked last season after admitting to Christopher she was ratting to the feds.
"I don't know; they always write such good stuff that I never worry about that," he said. "But I always thought that [Christopher's] story is going to end tragically — I'm convinced of that for all of us.
"It's not going to be pretty."
Imperioli's "Law & Order" story will team him with Dennis Farina while series co-star Jesse L. Martin (Green) takes time off to co-star in in the movie version of "Rent" (he starred in the original Broadway production).
"What I find interesting about the character of Nick Falco is that he probably comes from a similar background as Christopher," Imperioli said. "They're both Italian-American and are both New Yorkers.
"But I think Nick probably comes from a family where people are involved in law enforcement, and Christopher is from a family where people are involved in organized crime."