If we see the implementation of a pitch clock in an attempt to speed up the pace of play in 2018, it will be nothing new to the scores of players who have come up through the Minor League ranks in recent years.

The pitch clock has been a part of life at the Double-A and Triple-A levels since 2015. So players like Indians outfielder Greg Allen , who was in Double-A in '16 and '17, have already adjusted to playing ball on the clock.

"At first, you're a little over-conscious of it, with it being so new," Allen said. "But the more time that you spend with these game clocks, it becomes more of a normal aspect of the game. You don't pay attention to it too much."

That's an important point to consider at a time when MLB and the players' union disagree on how best to address the lengthening game times at the Major League level. Sources told MLB.com's Jon Paul Morosi that this past week, the MLBPA rejected MLB's most recent proposal regarding pace of play rules, which included a pitch clock and limitations on catchers' mound visits per inning.

Baseball's Collective Bargaining Agreement permits MLB to impose on-field changes unilaterally when at least one year of notice is given to the union, and MLB initiated that process early in 2017. But Commissioner Rob Manfred has said his preference is to make changes with MLBPA cooperation. Manfred and MLBPA executive director Tony Clark are reportedly slated to meet this coming week to discuss the issue further.

Across the game, there is a desire for clarity with regard to rule changes before the exhibition season begins.

"We have to be in position to prepare our players with what the rule changes are," Twins chief baseball officer Derek Falvey said. "It goes unnoticed, but it's something in Spring Training where you have to make sure guys are prepared for it. You have to come up with a different routine. So hopefully they tell us soon."

Indians reliever Andrew Miller , one of four elected MLBPA player representatives, said he understands why Major League Baseball wants to improve the pace of play, but doesn't agree with what was proposed.

"Everybody agrees we can be better and everybody agrees it would be a positive if we get games to move a little bit better, be shorter and the downtime was tightened up," Miller said. "It's just how to get there. A lot of players, myself included, are not fans of the pitch clock. This isn't something we're trying to pick a fight on. It's more just how you get there."

Despite the rejection by the union at large, some veteran players don't mind the pitch clock idea.

"I don't think players want to be there for three and a half hours, fans don't want to be there for three and a half hours and umpires don't want to be there for three and a half hours," Red Sox ace Chris Sale said. "I like working pretty quick, keeping my guys behind me in it. Plus, there's not much else to do. You're the only guy out there. Catch the ball, get on the mound and throw it. I'm a fan of it, but I don't speak for everybody on that."

With last season's average game coming in at three hours, five minutes -- the longest in MLB history -- MLB has shown interest in adopting a clock similar to the ones employed in the high levels of the Minors, where there is a 20-second limit between pitches with no runners on base. Umpires have the discretion to issue warnings, but pitchers charged with violating the rule are called for an automatic ball and batters are called for an automatic strike.

According to Baseball America, in the five Double-A and Triple-A leagues with pitch clocks, the average nine-inning game time dropped dramatically in 2015, when pitch clocks were instituted, before rising the next two seasons. In '15, the average game time in the Pacific Coast League dropped 13 minutes and the International League dropped 16 minutes. In the two years since, both of those leagues have seen a total increase of eight minutes, which means the technology has still been effective in speeding up the game relative to 2014, but not to the extreme degree witnessed in the first year in which it was utilized.

Those who have come up through those levels in recent years can speak to the impact the pitch clock has on proceedings.

"Honestly, you don't even notice," said Rangers pitcher Austin Bibens-Dirkx , who pitched in 11 Minor League seasons before reaching the big leagues last year. "Your job is to get outs. Honestly, that is how I took it. I know some other guys struggled with it, but I didn't even notice it. I just got up there, took my sign and didn't worry about the [clock]."

Allen said it was rare to see automatic balls and strikes applied.

"Sometimes [umpires] would give guys more leeway, other times they were more strict," Allen said. "All in all, the amount of times a guy actually had a ball or strike called wasn't a high number. But the fact that guys are aware of the clock is what makes the biggest difference."

Tribe pitcher Mike Clevinger, who has spent the last two seasons bouncing between Triple-A and the big leagues, felt similarly, but said established big leaguers might have a harder time making the adjustment.

"I feel like it might even cause more of a delay," Clevinger said. "Because once it gets called, how many people are going to come talk to the umpire? So now we're looking at three minutes of arguing instead of the 45 seconds it took someone to do their Nomar Garciaparra routine to get in the box."

Speaking of former members of the Red Sox, David Ortiz said he supports MLB's effort to pick up the pace.

"They do [have to pick up the pace], because the game is turning a little boring because of the time," Ortiz said. "Now that I'm on this side watching the game, I know. When you're watching a three- or four-hour game, it gets a little complicated. I think MLB needs to do whatever it takes to keep up with the pace of the game. The thing is, if you want to have the millennials watching the game, you definitely need to do something, because this is the ADD that comes with this new generation."

Blue Jays manager John Gibbons said he has no issue with the clock, but he is more concerned about the potential limitation of mound visits.

"I don't like seeing catchers going out to the mound all the time, but sometimes you need it," Gibbons said. "Whether it's to change a sign or when you bring in a new kid up here, first time up, or new to the organization. There are some things in game early on that they need to talk things out. That might present a problem throughout the league but the pitch clock, I think everybody can deal with that."