The serious negotiations over Major League Baseball's pace-of-play initiatives haven't really started yet and probably won't for weeks to come. Once MLB and the Players Association dig into their talks, there will be haggling over the particulars of some ideas, like restrictions on the number of mound visits.

But the foundation of the changes to come in 2018 will be in the implementation of a pitch clock, sources say, and MLB is intent on using the same limit used in the minor leagues the past three seasons -- 20 seconds between pitches when there are no runners on base.

Not 25 seconds.

Not 18 seconds.

Twenty seconds, with pitchers required to begin their motion within 20 seconds of the previous pitch.

After informal conversations between MLB and the players' union in August, some players walked away from those meetings resigned to the idea that, one way or another, a pitch clock would be put in place for 2018. They wondered, however, if the time between pitches might be negotiated to 22 seconds or 24 seconds.