Major League Baseball's new pace-of-game rules already appear to be having a major impact early this season.

According to MLB, the new rules helped to cut nearly eight minutes off the average time of a nine-inning game over the first week of the 2015 season.

The general consensus among players and baseball officials is that between-inning clocks have had the greatest impact on MLB's effort to speed up the pace of the game. Jeff Zelevansky/Getty Images

Through the first Sunday of this season, there were 79 nine-inning games, compared with 85 at the same stage last year. The average length of those games this year has been 2 hours, 54 minutes, 39 seconds. A year ago, the average was 3 hours, 2 minutes and 25 seconds.

Although it is difficult to know if this trend will hold, the average game time through the first week last season varied very little over the course of the season, finishing at 3 hours, 2 minutes and 21 seconds.

If MLB can maintain this game time, it would be the first time the average time of a nine-inning game has slipped below 2 hours, 55 minutes since 2011. After a 15-year period in which game times averaged in the neighborhood of 2:50, those times had jumped dramatically over the past three seasons -- to 2:55:58 in 2012, 2:58:52 in 2013 and 3:02:21 last year, according to the Elias Sports Bureau.

However, baseball commissioner Rob Manfred recently told ESPN.com that he isn't measuring the impact of the new rules with a clock alone.

"I'm really not thinking about this in terms of average game time," Manfred said in an interview just before Opening Day. "It's not like I have in my head I want to get from 3:02 to 2:58 or 2:55. That's not what it's about for me.

"What I hope happens is that, at the end of the season, knowledgeable baseball writers and fans are saying, 'You know, they got this one right. There's a crispness to the play. They've cleaned up some dead time in the game. And maybe best of all, we feel like they were responsive to what people were saying about the game.'"

MLB introduced three significant changes this season in an attempt to move games along at a crisper pace:

• With certain exceptions, hitters must keep one foot in the batter's box between pitches throughout their at-bat.

• Each ballpark now has between-inning countdown timers to ensure that the next half-inning starts promptly. The timers are set at 2 minutes, 25 seconds for most games and 2:45 for nationally televised games. Pitchers and hitters have been encouraged to be ready to go when the clock reaches 20 seconds.

• Managers can now signal instant-replay challenges to umpires from the dugout area, instead of from the field.

MLB has not broken down the impact each of those changes has had on game times, but the general consensus among players and baseball officials is that the between-inning timers have had the greatest effect by cleaning up excess time before the start of each half-inning. Manfred said that was one of baseball's chief concerns, as the time between innings often stretched beyond 3 minutes last season.

"I think fans understand and appreciate the fact that there are certain, naturally, never-going-to-be-changed aspects to the game that may not be fast-paced," the commissioner told ESPN.com. "What I think people were concerned about was things that they saw as not integral to the play of the game, or even the economic setup of the game.

"We don't need to be at 3:20 [between innings]. Why do we need to be at 3:20? ... Those are the kind of things that you can tighten up, shorten up, without affecting the flow of the game."