The NFL says this season it will emphasize the defensive holding penalty and the illegal contact penalty. This is a big development, emphasizing these points of emphasis. It will help the 49ers and I will explain why.

But first, can you explain how a penalty can be a point of emphasis?

I don’t get it. Why would something that is already a penalty need emphasis? A penalty is a penalty is a penalty.

Hey, officials, call it. There’s your point of emphasis.

After God dictated the Ten Commandments to Moses on Mount Sinai, God didn’t say, “Moses, make sure you emphasize the Seventh Commandment; I’m serious about that one and I’m watching.”

Defensive holding and illegal contact have been penalties in the NFL rule book for decades – the officials just haven’t called those penalties consistently. Officials mostly have let cornerbacks play physically the past decade. You may want to substitute “dirty” for “physically.”

Which created a problem for the league. Defensive players and defensive coaches have bent the rules in their favor. Naturally. If a penalty is not enforced, why honor it? Is a penalty really a penalty if officials don’t enforce it?

The NFL doesn’t want to slow down the game, so in the past defensive holding paid off because the officials called only a few of those penalties every game. And when the officials penalized defensive holding, it was just a 5-yard penalty. This was the key equation. Officials hardly called defensive holding and when they did the price was small. So if you were a defensive back, sure, you’d pull jerseys and get away with fouls like the villains in pro wrestling.

The Seattle Seahawks have gamed the system especially well. It’s what they do. Former vice president of NFL officiating Mike Pereira told the Wall Street Journal that the Seahawks believe they “may get called for one (defensive holding or illegal contact penalty), but not 10.”

Pereira told the Wall Street Journal the Seahawks sometimes intentionally commit a blatant defensive holding call early in a game. “They want to see what kind of tone the officials are going to set,” Pereira said. It’s a diagnostic penalty. Will the officials call the penalty or won’t they?

The Seahawks publicly brag about how they work the system. Last October, Seahawks defensive coordinator Dan Quinn told the Seattle Times, “We try to … educate what’s going on around the league, in terms of, ‘This was called in this game. This was called in this game.’ … For us, it’s important just to know what’s kind of the climate of how it’s being called.”

Mistake. Not that Quinn bent the rules, but that he talked about bending them. He’s supposed to lie and say he coaches to the letter of the law. But he said he coaches to the interpretation of the law. He scouts the officials. He’s not the only person who does that, but he is the only person who admits doing it. The NFL does not like when coaches or players flaunt their disregard for the rules. When the NFL gets embarrassed, it takes revenge.

According to ESPN Stats & Information, defensive holding and illegal contact were called on 1.1 percent of pass plays during the 2013 preseason, and they were called on 1.6 percent of pass plays during the 2013 regular season. But during the first week of this year’s preseason, those defensive penalties were called on a whopping 8 percent of pass plays. Regular season games are going to take four hours if officials continue to call penalties at this rate.

It is possible the league is making a big stink in the preseason, hoping that defensive players and coaches get the message to cease and desist, and then the penalties will taper off when the regular season begins.

It also is possible the penalties will not taper off. Don’t be surprised if the officials throw a flag every single time a defender grabs a jersey more than 5 yards down field. Don’t be surprised if the Seahawks’ defense sets a record for most penalties ever committed during a season.

The 49ers need the second possibility to happen. The 49ers will not have their two best defensive players – NaVorro Bowman, Aldon Smith – for a good chunk of the first part of the season. In 2010, the season before Bowmand and Smith were starters, the 49ers’ defense ranked 16th in points allowed. Mediocre. They could be mediocre again until Bowman and Smith return.

The Seahawks’ defense could be mediocre, too. If its players can’t hold receivers, the Seahawks could lose their edge on the rest of the league.

Advantage 49ers.

Grant Cohn writes sports columns and the “Inside the 49ers” blog for The Press Democrat’s website. You can reach him at grantcohn@gmail.com.