One of Major League Baseball's latest controversies calls to mind a bit from the 2009 Star Trek, in which Dr. McCoy offers words of wisdom to Mr. Spock.

"You know, back home we have a saying: 'If you're gonna ride in the Kentucky Derby, you don't leave your prize stallion in the stable.'"

This applied to Kris Bryant back in 2015, and to Ronald Acuna Jr. earlier in 2018. Right now, it applies to Vladimir Guerrero Jr., Eloy Jimenez and Peter Alonso.

The arrival of expanded rosters on Sept. 1 also marked the arrival of cup-of-coffee season for deserving players from the minor leagues. Because each one is a top-rated prospect who's put up huge numbers in the high minors, there's little doubt Guerrero, Jimenez and Alonso should be among the lucky coffee drinkers. If anything, they all deserved to be promoted a lot sooner than September.

Yet they are nowhere to be seen. Guerrero is not with the Toronto Blue Jays. Jimenez isn't with the Chicago White Sox. Nor is Alonso with the New York Mets.

Such is the effect of the menace known as "service-time manipulation."

For anyone who needs a quick primer, this is the practice that sees teams keep players in the minors until they have secured their services for an additional year.

A player can't reach free agency until he's played six seasons in the majors. But while an MLB season plays out over roughly 180 days, a player qualifies as having played in a "season" if he's in the majors for at least 172 days. Any less than that, and he falls short.

So if a team waits to bring along a top prospect until after the 172-day cutoff, it can control him for the remainder of that season plus six more afterward. In effect, that player has to wait seven years until free agency.

Hence Guerrero, Jimenez and Alonso probably won't be seen until the middle of April 2019, when the fateful cutoff will have come and gone.

As Sheryl Ring wrote for FanGraphs in March, there's a possible legal argument against service-time manipulation—that teams who engage in it aren't acting in good faith with regard to competitive aspirations.

Where things get complicated is that when prospects are ready for The Show is subjective. There isn't a set of boxes to check. Clubs are free to determine their readiness based on...well, whatever.

Back in '15, the Chicago Cubs asserted that Bryant needed to improve his defense. Earlier this year, the Atlanta Braves reasoned that a 20-year-old Acuna shouldn't be rushed to the majors.

These excuses are echoing in the official arguments against calling up Guerrero, Jimenez and Alonso. For instance, here's White Sox general manager Rick Hahn on Jimenez, per James Fegan of The Athletic:

Likewise, Mets GM John Ricco insisted that Alonso, 23, also must "keep working on his defense," according to Matt Ehalt of NorthJersey.com.

Per John Lott of The Athletic, defense is only one concern that Blue Jays president Mark Shapiro has about Guerrero. He also brought up the 19-year-old's game preparation and "nutrition."

Thus, are the powers that be in Toronto, Chicago and New York playing the part of Spock, who responded to McCoy by saying: "A curious metaphor, doctor, as a stallion must first be broken before it can reach its potential." 

However, the official excuses ring hollow.

The Blue Jays, White Sox and Mets aren't in the postseason picture, so there's no reason why Guerrero, Jimenez and Alonso can't work on their defense in the majors. Beyond that, their MLB-readiness, from an offensive standpoint, is evident in their 2018 numbers:

• Guerrero: 1.073 OPS and 20 HR
• Jimenez: .961 OPS and 22 HR
• Alonso: .975 OPS and 36 HR

And while there have been times when Major League Baseball has been no country for young men, this is not one of those.

As Joe Sheehan noted at Baseball America in June, the 2010s have housed more talented 21-and-under players—including Mike Trout, Bryce Harper, Carlos Correa, Francisco Lindor, Corey Seager, Cody Bellinger and, most recently, Acuna, Gleyber Torres and Juan Soto—than each of the three previous decades. 

If the focus is narrowed to MLB's recent expansion era (since 1993), FanGraphs' WAR reveals that rookies of all ages have been holding their own with the big boys for a while now:

The effort to push performance-enhancing drugs out of MLB has weeded out unnaturally ageless players, opening the door for younger stars to take over. And as Sheehan's piece covers, young players have come up through an increasingly specialized youth sports scene, wherein they sharpen the raw tools (e.g., power, speed and velocity) that the modern game is centered around.

So strictly from a perspective of how best to play competitive baseball, the idea that young stallions need to be broken before they can be used doesn't hold as much water.

As far as the business perspective is concerned, it's nigh impossible to refute that teams that stretch six years of control to seven years are doing the right thing for their own interests.

This is problematic for Major League Baseball as an institution, however, for a simple reason: Fans really want to see the best young players.

One need only look to any recent All-Star Game to see a strong correlation between the youngest stars and the most popular stars. Many were fan favorites even before they broke into the big leagues, as modern advancements have contributed to a huge uptick of interest in prospects.

As MLB.com's Jonathan Mayo told Dave Sheinin of the Washington Post:

"It's exploding exponentially. Every time I think, 'Well, this is where we're at,' all of a sudden there's more people following. It's [the result of] the growth of media and social media. It used to be you didn't even know what these guys looked like until they got to the big leagues. Now you can watch thousands of games online."

In an environment like this, it's no wonder that the pushback against service-time manipulation is getting stronger.

The MLB Players Association has gone to bat for Bryant and Guerrero. Jimenez's representatives are speaking out on his behalf, just as agent Scott Boras once did for Bryant. And this is only the latest in a line of articles (see also: Baseball America, The Athletic and CBSSports.com) decrying service-time manipulation.

Momentum for change is building at an opportune time. With baseball's collective bargaining agreement due to expire in 2021, it won't be long before negotiations over a new CBA get serious.

The union is certain to pursue an overhaul of MLB's free-agency rules—which could involve simply redefining a season or a more drastic measure to base free agency on age—that would allow for players to reach the majors and hit the open market sooner. The goal will be to funnel more money to players, who have been getting a smaller slice of the pie lately.

With stakes this big, the conflict between the MLBPA and MLB could get ugly. The possibility of a work stoppage is real.

Yet the league knows it has to make every effort to appeal to younger fans, so that's one reason to bend the rules in favor of young players. Doing so could also lead to the death of MLB's sudden tanking epidemic. If clubs call on their young players sooner and become more willing to invest in free agency, the number of competitive teams could increase. That's good for business.

For now, there's only outrage. But out of outrage must come hope for positive change. Maybe, just maybe, that's what will happen.