There are a variety of reasons why coaches’ script plays in the NFL. The idea was originally brought into the league by none other than Bill Walsh. In his book: Building A Champion he offers the following:

Head coach Paul Brown would say, “What do we have for openers?” So, on game day, offensive-line coach Bill Johnson and I would agree on 4 plays we could call at the start of the game. Paul was comfortable with that. Then it was 6 plays. In 1976 while an assistant coach for the Chargers, I planned a 15-play sequence.

As time passed, that format was extended to 25 plays. After I left the Chargers to coach Stanford, the strategy was so successful that we scored on our first possession eight times in eleven games in 1978. But during the 1980’s, the “scripted” offense was the hallmark of the 49ers.

Some people thought we called 25 plays, come hell or high water, which assume that if we were on the one-yard line after our eight play, we’d call a long pass. Obviously the system had to be much more flexible than that to be successful.

We had special categories for each situation, every thing from goal-line plays to extreme-long-yardage situations. We would construct a “ready list” with the opening plays but also have plays listed for specific categories.

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So in all these categories, we had priorities. We didn’t always go directly to them because as the game went on, we would analyze our opponent’s strategy and make adjustments. But with all those considerations isolated, we could put together 25 plays that would enable us to smoothly begin the game, proceeding with our best chance of success.

Walsh goes on to explain that the “Ready List” he speaks of was designed because of an instance he had while working for the Bengals against the Raiders in Oakland. Walsh’s team was trailing by only three points, and had time to move the ball into field goal position. However, because he didn’t have his “Ready List” certain plays that would have been perfect for the situation only occurred to him after the team had already lost the game. It was at that point that Walsh vowed never to have repeat of the situation.

Walsh writes a whole chapter on scripting plays in his book - which by the way is the best book I have ever read regarding the 49ers. And in his book, as seen above, Walsh speaks of scripting 25 plays - not the 15 that became synonymous with the 49ers. So why the difference?

The difference in numbers is that Walsh would script 25 plays and run as many of them at the beginning of a game as possible, but only under certain situations. He did also have a sequence of scripted plays within his 25 play Ready List to call at the beginning of the game. That sequence was developed as method with San Diego Chargers. The ten other plays, as Walsh describes are for ‘special’ situations.

Current head coach of the 49ers Steve Mariucci learned the West Coast Offense from Mike Holmgren, who ironically will be coaching the 49ers opponent this week. It was under the tutelage of Holmgren a Walsh disciple himself that Mariucci learned to script his offense.

While coaching the UCLA Bruins Mariucci would script the first 18 plays of each game - in honor of starting quarterback Pat Barnes (who incidentally has spent some time as an emergency quarterback for the 49ers). Mariucci thus was not afraid to change tradition and go with a 19 play script with the 49ers.