Ask Farmer: How many play in an NFL playbook, and how many do teams run in a game?

Have a question about the NFL? Ask Times NFL writer Sam Farmer, and he will answer as many as he can online and in the Sunday editions of the newspaper throughout the season. Email questions to: sam.farmer@latimes.com

How many different plays are in a typical NFL playbook? And, in the course of a game, how many different ones will a team usually run?

--Jack Erskine, La Cañada

Farmer: Back when he was coaching, Jon Gruden had a playbook thicker than the Los Angeles Yellow Pages — remember those? — so I asked him your question. He said that while there are hundreds of plays in a typical playbook, most teams select between 75 and 100 pass plays for a game, and 15-20 running plays when assembling a game plan for a given week.

“If you see Tom Brady or Drew Brees, the veteran quarterbacks, you might have more than 100 pass plays in a game plan,” said Gruden, who won a Super Bowl with Tampa Bay and now is an ESPN “Monday Night Football” analyst. Some of those will be contingency plays, in case somebody gets hurt and you only have limited personnel. For instance, if you activate two tight ends for a game, and one gets hurt, you have to dump all your two-tight-end plays and turn to a contingency plan.

There are plays for all sorts of situations — two-minute drill, goal line, short yardage, backed up against your own goal line, desperation plays, trickery — and all are built into every game plan.

You’ve seen quarterbacks who wear a wristband with plays written on them in tiny type, right?

“When they open up those wristbands, they might have passes running all along the top and runs on the bottom,” Gruden said. “And on the far right you might put all the red-zone plays.”

Now, the important question: Do those plays work?

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Why is it that all footballs, from Pop Warner to NCAA Division I, have white rings on the ends, but the NFL there are no white rings?

--Steve Salzman, Riverside

Farmer: Those white stripes are to make the footballs more visible, particularly in late afternoon and night games, and the became standard back when fields were not as well lighted.

Whereas college footballs have had white stripes for nearly a century, the NFL has experimented with different colored footballs — including a white ball with black stripes. Players in the 1940s likened that to playing catch with an egg, and complained it almost disappeared against a backdrop of white jerseys. Eventually, as lighting improved, the NFL went to a brown ball without stripes in part to distinguish itself from the college game.