A recent report indicates that Special Counsel Robert Mueller's investigation is nearing its end, but former independent counsel Ken Starr isn't so sure.

NBC News reported Thursday that Mueller is expected to submit a confidential report on Russian election interference to the attorney general as early as mid-February, citing government officials and others familiar with the situation.

Appearing on "Outnumbered Overtime" Friday, Starr said that timeline may be "a little bit optimistic."

"It looks as if Bob Mueller's rounding third base, but he's also the third base coach," Starr said. "So he can say, 'Halt!'"

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He said one thing that could extend the probe is if Mueller insists on an in-person interview with President Trump, who has already submitted written answers to questions from Mueller through his legal team.

He said if Trump's attorneys absolutely will not allow Mueller's team to interview the president, then the special counsel will be left with a tough choice.

"Does he go to the grand jury and say, 'I want to subpoena the president.' And then we have a constitutional standoff," Starr said, adding that's a "big if."

He noted that in his investigation of then-President Bill Clinton, he repeatedly tried to get an interview, but it never materialized. Eventually, he went to the grand jury and they "readily" issued a subpoena.

"So let's see," Starr said.

Watch more from Starr above.

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