Holding penalties in the NFL plummeted Sunday following a conference call between senior vice president of officiating Al Riveron and referees.

Officials threw 41 flags for offensive holding in 14 games Sunday, an average of 2.9 per game, according to ESPN Stats & Information research. In the first 33 games of the season, there were 188 such flags, a rate of 5.7 per game.

It is not unusual for Riveron to hold conference calls with referees during the season, and he addressed multiple topics Saturday night. But the focus of the call was offensive holding, a narrow point of emphasis for 2019 that had morphed into a more significant issue.

The final straw was Thursday's game between the Tennessee Titans and Jacksonville Jaguars, in which referee Shawn Hochuli's crew threw 10 flags for offensive holding. New England Patriots quarterback Tom Brady tweeted that he turned off the game because he couldn't watch the "ridiculous penalties."

Brady addressed his tweets directed at Hochuli's crew in his weekly Westwood One interview that aired Monday night, explaining how both teams weren't allowed to play the kind of physical, hard-nosed football he likes.

"I'm a fan of the NFL. I'm a fan of football," he said. "More so than anything, I've been a fan of this game for 40 years of my life. My parents had me in the stands at Candlestick Park when Joe Montana threw to Dwight Clark and 'The Catch.' As a fan of the sport when I'm watching the game, I want to see good, clean, hard-nosed football, and I'm a little bit of an old-school player in that way because for playing in this game for 20 years, you know, I recognize the many rules changes, the influence of the media, the influence of society. I want to see tough, hard-nosed football. When I was watching the other night, I decided to turn it off 'cause I didn't feel like that's what I was seeing, and that's all I was saying."

This summer, the NFL asked officials to focus on a technique sometimes referred to as a "lobster block," in which an offensive lineman wraps his arms around a defender while blocking on the backside of running plays. As it turned out, the officials increased their focus on holding all over the field.

In the first two weeks of the season, they threw 178 flags for offensive holding -- a 66% increase from the same time period in 2018. The spike contributed to a 16.2% increase in total penalties compared to Weeks 1-2 of last season, as well as a slight drop in scoring from 21.97 offensive points per game in 2018 to 20.9 in 2019.

During Saturday's call, Riveron instructed referees to continue emphasizing the need for offensive linemen to immediately move their blocks inside the frame of the defender if they initiate the block outside. But on front-side and other blocks, Riveron counseled them to allow more time to get inside the frame.

Riveron's effort followed the trend for points of emphasis, which usually lead to a surge in calls during the preseason and the early part of the regular season. In some cases, coaches and players adjust, and the flag rate flattens out. In other cases, the NFL officiating office or the competition committee steps in to mandate an adjustment.