How Nick Saban Made It to Alabama’s Kickoff on Saturday

Still, Dr. O’Neal said she had worried about endorsing a protocol that “debunks a test result.”

“There’s so much attention around the validity of these tests, and for us who work in health care, just convincing patients to trust us and trust getting tested has become a struggle,” she said. “We don’t want to give the perception that we don’t believe these tests.”

The tipping point, she recalled in an interview Tuesday, had been “the increased awareness that false positives do occur.”

Despite the slight variances of the SEC’s new protocol from others’ guidelines, outside experts said that a lone positive result among so many negative P.C.R. tests was almost certainly inaccurate.

Rules made clear that Saban could not coach, even from home, if he had the virus. If Alabama wanted Saban in charge against Georgia, the new approach was its only option. And even if the plan worked, it would not be clear until sometime Saturday, the day of a game long seen as one to shape the race toward the College Football Playoff.

Less than 24 hours after the positive result, Saban took the first of the three SEC-sanctioned tests he would need to pass to exit isolation.

His first formal follow-up tests, conducted around 7 a.m. on Thursday and Friday, showed negative results, as did two other P.C.R. tests that Alabama ordered “out of an abundance of caution” at another lab. Alabama announced the first SEC test’s results, and ESPN reported the findings of the second as it broadcast from Alabama’s stadium on Saturday morning.

Word had already begun to circulate through the SEC that Saban might prove eligible to coach.

Driving the last specimen to Mobile would have taken more than three hours on game day, potentially stripping Saban of precious time with his team. So Alabama athletics turned to its speediest option: its jet.