Mr. Armisen will still have an enormous amount to do, Mr. Michaels said, describing that 10-year player as “the backbone of the show now.”

That might also describe Seth Meyers, a cast member and the show’s head writer who was also the subject of rumors this summer that he would replace Regis Philbin as Kelly Ripa’s sidekick on “Live.”

“I personally didn’t think I’d be losing Seth,” Mr. Michaels said, “though I read that I could be.”

With three vacancies Mr. Michaels was compelled to recruit new players. He turned to the Second City troupe in Chicago, long a pipeline to “SNL.” Several performers were invited to audition on the “SNL” stage, where they get about seven minutes to perform characters, deliver impressions and be funny. “Part of it is just how they stand on that stage,” Mr. Michaels said. “Can they take the stress of that?”

He came up with three survivors: Aidy Bryant, Cicely Strong and Tim Robinson. They will join the holdover cast and the guest host Seth MacFarlane (creator of “Family Guy” and the man behind the film “Ted”) for the 38th season premiere on Saturday. “SNL” is returning a week earlier than usual, specifically to jump on the political news. That means references to the conventions, Mr. Michaels said. “We have at least three different takes on Clint,” he said, referring to Clint Eastwood’s memorable colloquy with furniture. (Bill Hader will play him.)

Taran Killam, who has been emerging as a breakout player, is Mr. Michaels’s likely choice for Mr. Romney’s running mate, Paul Ryan, though he said that character may or may not appear this week. But Mr. Michaels acknowledged that Mr. Obama has been a challenge. What is his comedy hook? “So far we haven’t found it. My joke is always that he’s the first Canadian president,” said Mr. Michaels, a Toronto native. “He wants to think it through, do it in the fairest way possible and be thoughtful. And be a little distant, which I totally identify with, obviously.”

Mr. Romney? “He’s easy to play because of that caution of his.”

The show’s overall take on the election will continue to take shape. “We won’t know where we’re going until the first debate,” he said.

Mr. Michaels’s input will be more as editor than dictator.

“We talk it down,” he said, adding, “If it’s funny, we’ll use it. If it isn’t, we won’t.”