Television viewers first noticed the aberration on Sept. 10, during the first week of the N.F.L. season, when it happened several times before a live audience of millions of people. Then, the following week, there it was again — and then the week after that, too.

By now it is a full-blown TV marvel, appointment viewing for the N.F.L.’s legion of fans: an announcer who can predict what play is going to happen on the field before the ball is snapped. He’s that good.

The announcer is Tony Romo, and he was making his broadcasting debut on CBS in that Sept. 10 game. But he was no stranger to fans. Before this gig, he was the star quarterback for the Dallas Cowboys the past 14 seasons.

Lots of former players have moved into the broadcast booth after their playing careers, but none have upended convention and delighted fans as much as Romo has through the first few weeks of this season. More often, the ex-players resort to hackneyed sports jargon and observations that even casual fans consider obvious.