FOXBOROUGH, Mass. — When Bill Belichick roams the sidelines during a New England Patriots game, it is remarkable how often he is altogether alone. Belichick has more than a dozen assistant coaches, but few approach him. There are nearly 50 players, but they tend to scrupulously avoid their head coach.

Typically, there is a buffer of about 20 feet between Belichick and any other person for most of the three hours it takes to play an N.F.L. game.

Standing near the sideline throng, Belichick is amid his team but apart as well.

On Saturday night, as the Patriots hosted the Tennessee Titans in a divisional-round playoff game, there was no moment when Belichick appeared more alone than late in the first quarter.

The Titans had just silenced the raucous New England crowd, scoring the game’s first points on a methodical 11-play touchdown drive.