The pace of play in Major League Baseball is one of the top priorities for new commissioner Rob Manfred. There will be changes to the rules in 2015 and Manfred will announce what they are on Friday.

Just a few months ago during the Arizona Fall League, the MLB experimented with numerous initiatives to improve the pace of play. It's been said no major changes will be instituted this upcoming season, but the league will begin implementing minor measures to begin the gradual process. According to FOX Sports' Ken Rosenthal, here are four key points Manfred will talk about today:

-Managers must challenge replays from the dugout.

-Batters must keep one foot in the batter's box unless an "established exemption" occurs.

-Play to resume promptly once broadcast returns from commercial break.

-Pitching changes will be timed and violations will include minimal fees (two minutes and 30 seconds).

The Arizona Fall League tested the batter's box rule and timed pitching changes. They also experimented with no-pitch intentional walks, a 20-second rule for pitchers with the use of a pitch clock (discourages 'unnecessary' delays by pitcher), a break limit in between innings (two minutes and five seconds) and a three "time out" limit (conferences with pitchers or batters). The league witnessed a ten minute decrease in average time per game and a 13-minute decrease in average game time base on plate appearances.

Manfred's goal is to "bring more people into our game - at all levels and from all communities." It's believed he's particularly focusing on appealing to the younger fans, which the league believes they're losing out on for a number of reasons, including a decade-high average run-time for MLB games (three hours and two minutes). For some perspective, that number was at two hours and 33 minutes back in 1981.

According to ESPN's Jayson Stark, "two timers will be used in every major league ballpark to help quicken the pace. For each half-inning break, teams will have either 2 minutes, 25 seconds (for local telecasts) or 2 minutes, 45 seconds (national telecasts) from the time the commercial break begins until the first pitch should be thrown to the next batter, who should be in the batter's box with no fewer than 20 seconds remaining on that timer."

The league has also considered shrinking the strike zone to help boost the offense and increase runs scored per game, which was also the worst in 2014 (4.07) since 1981 (4.00).

We'll provide an update once Manfred speaks later today.

UPDATE: Check out the official changes below.