The new pace of play rules, explained

Coming off a 2017 season that saw the highest average game time (three hours, five minutes) in history, Major League Baseball and the MLB Players Association had much discussion prior to Spring Training on how to speed things up. On Monday, Commissioner Rob Manfred announced some rule changes aimed at pace of play.
Here's everything you need to know about those changes:
What's different?
There will be limits on mound visits, the length of time between innings and during pitching changes.
• MLB announces pace of play initiatives for '18
But what about the pitch clock?
Despite many rumblings about the potential implementation of a pitch clock, that change will not be made for 2018.
How many mound visits are allowed?
Six per team per nine innings. If a game goes to extra innings, each team will receive one additional non-pitching-change mound visit per inning. Note, too, that the prior rule that a pitcher must be removed on the second visit by a manager or coach in a given inning remains in effect.

OK, so what qualifies as a "mound visit"?
This is important, because it's not just a manager or coach visit to the mound to meet with the pitcher. It is also a player leaving his position to confer with the pitcher or a pitcher leaving the mound to confer with another player, regardless of where the visit occurs or the length of the visit.
That said, there are interactions that don't qualify as mound visits, including:
• If the visit is made due to an injury (or potential injury) to the pitcher
• If the pitcher and position player interact between batters without relocating
• If a position player goes to the mound to clean his spikes in rainy conditions
• If the visit is made immediately after the announcement of an offensive substitution
• Players, managers react to changes
Are there any instances in which a team will get extra mound visits?
Just one. If a team has used up all of its mound visits but a home-plate umpire determines that the pitcher and catcher did not have a shared understanding of the location or type of pitch that had been signaled (in other words, if the two were "crossed up"), the umpire may, upon request of the catcher, allow the catcher to make a brief mound visit.
Note that the "cross-up" situation applies to a team's allotment of six visits per nine innings if the team has not already exhausted its allotment.

How long will the breaks between innings and pitching changes be?
As has been the case since the start of the 2016 season, the breaks will be as follows: two minutes and five seconds for locally broadcast games and 2:25 for national televised games. For tiebreaker and postseason games it will be 2:55. Previously, the between-innings break was 2:25 for locally broadcast games and 2:45 for nationally broadcast games.
When does the inning break begin?
On the final out of the inning, unless that out is a close play that may be reviewed (in which case the timer will begin as soon as the umpire signals an out) or unless the pitcher ends the inning on base, on-deck or at-bat (in which case the timer will begin when the pitcher leaves the dugout for the mound) or the catcher ends the inning on base, on-deck or at-bat (in which case the timer will reset when the catcher enters the dugout and another catcher must begin warming up the pitcher).
During the playing of "God Bless America" or any other extended-inning event previously approved by the Office of the Commissioner, the timer will begin at the conclusion of the song or event.
When does the pitching-change break begin?
As soon as the relief pitcher crosses the warning track (or foul line for on-field bullpens).
How will the time limitations be implemented?
With 25 seconds left on the timer, the umpire will signal to the pitcher to complete his last warmup pitch, which must be delivered before the clock strikes 20. At 20 seconds, the batter will be announced and must leave the on-deck circle. At zero seconds, the pitcher must began his motion to deliver the first pitch of the inning. (Even if everybody is ready, the pitcher cannot deliver the first pitch more than five seconds before the end of the timer, so that the broadcast is ensured to be back from commercial break.)
There are a few special circumstances in which the break will be extended, including:
• A delay in normal warmup activities through no fault of the players, such as an injury or medical emergency, equipment issues or playing field or grounds crew issues
• The umpire believes the pitcher is at legitimate risk of injury if he does not receive additional time to throw warmup pitches
• The umpire believes the batter is at risk of injury if he does not receive additional time to enter the batter's box
• Any other circumstances in which, in the umpire's judgment, more time is needed
So are pitchers still guaranteed eight warmup pitches?
Nope. They can throw as many warmup pitches as they are able in the allotted time, but the eight-pitch guarantee has been removed from the rule book.
What happens to those who break the rules?
Monday's announcement promises "progressive discipline" for players who consistently or flagrantly violate the time limits.
Will we see the pitch clock added in 2019?
It's still possible. The Commissioner's Office will monitor how much these changes impact the average time and the pace of games, and it is still possible that the pitch clock is imposed, with or without agreement from the MLB Players' Association, in future seasons.
MLB and the MLBPA have agreed to meet during the 2018 season to continue to discuss pace of play.
What about the batter's box rule installed in 2015?
This rule -- which requires hitters to keep at least one foot in the box between pitches -- is still in effect, though enforcement in recent seasons has not exactly been strict. It is possible that the increased attention on pace of play leads to increased enforcement.
What about the time it takes for replay reviews?
MLB is installing capability for all club video review rooms to receive direct slow-motion camera angles in an effort to expedite that process.
Any other changes?
New phone lines will be installed connecting the video review rooms and the dugout. MLB will monitor communication on those lines to prevent their use for sign-stealing.