Strange unwritten football rules the 49ers, rest of NFL face

49ers unwritten rule No. 2: Don’t leave points off the board

Being aggressive on 4th-and-goal situations is something every fan wants to see. And you know the scenario. It’s 4th-and-goal on the 1- or 2-yard line, and the fanbase at Levi’s Stadium is clamoring for head coach Kyle Shanahan to “go for it.”

Instead, the field-goal unit trots out and settles for a field goal amid a chorus of boos.

It makes sense, sure. Being aggressive is one way a top-tier offense can take advantage of any situation, yet one could also make the argument taking points off the board is a quick way to lose football games. A failed fourth-down attempt near the goal line is pretty bad, right?

Fortunately, Shanahan’s 2019 defense was No. 2 in the league in terms of points allowed. So it was fair to let the head coach trust his defense after settling for three. Yet there’s another reason why, at least in San Francisco’s case, settling for a field goal made a bit more sense than being too aggressive on fourth-down tries. Last year, the 49ers converted just 55.6 percent of their red-zone appearances into touchdowns, which was good for 20th best in the league.

Pehaps San Francisco should revisit this unwritten rule when its red-zone offense improves down the road.