San Francisco 49ers coach Jim Harbaugh was forced to spend some time away from his team just days before a very big game.

According to ESPN, Harbaugh, 49, had a minor procedure to correct an irregular heartbeat Wednesday and returned to his team on Thursday. He is expected to resume a normal schedule immediately and coach as usual on the night game against the Chicago Bears.

Patrick Willis of the San Francisco 49ers said, "Coach Harbaugh, like he always tells us, he's tougher than a two-dollar steak."

"We know he's going to all right."

According to The Washington Post, a 49ers spokesman said that Harbaugh met with doctors Wednesday night after feeling uncomfortable.

Mathew DeVane, a Walnut Creek, Calif., cardiologist and president of the East Bay Board of Directors of the American Heart Association, did not treat Harbaugh but said the NFL coach probably had atrial fibrillation, the most common abnormal heart rhythm.

"It can just cause the heart to race and flutter and can make you feel uncomfortable," DeVane told The San Francisco Chronicle. 

"It's a minor procedure and, again, this is guesswork, but it's called a cardioversion where we put the patient to sleep for just a few minutes and give the heart a little zap to try to reset it back into a normal rhythm," DeVane said. "It's a very, very common procedure. It's done on an outpatient basis. Usually people are home within two hours and ready to go the next day with no limitations or restrictions."

Factors that can trigger this uncomfortable feeling include stress, lack of sleep and too much caffeine, which is exactly what a coach's lifestyle is all about.

The condition can be treated with medication as well as behavior modification. But for Harbaugh who is known for his intensity, that might be unsuccessful.

"Sometimes I feel like there's five Jim Harbaughs in the building, because he's everywhere," quarterback Scott Tolzien said. "So today it was a little different with everyone wondering because he's always flying around."