Michael Kopech is mowing down hitters at Triple-A. Eloy Jimenez is hitting the cover off the ball at Double-A Birmingham.

Looking at the box scores from the minor leagues every day, you might wonder why these guys aren’t already playing big league ball on the South Side of Chicago. Looking at the major league club’s record, you might wonder why these guys aren’t already playing big league ball on the South Side of Chicago.

But don’t worry. Rick Hahn’s front office has its reasons.

Basically, they come down to the fact that, despite what the numbers say, these guys aren’t 100-percent major league ready just yet. Kopech has struck out 38 hitters in 30 innings. Jimenez has a 13-game hitting streak and a nine-game multi-hit streak. But that doesn’t cover every aspect of the game. There are things that don’t show up in the box score that Hahn & Co. are still wanting these guys to improve.

And in case you’re thinking of dusting off the old “even if they aren’t completely ready, how can they be any worse than what’s currently been happening at the major league level” argument, don’t. This season was billed as a rebuilding, developmental one from the start, and it’s been clear since the early stages of the offseason that the readiness of minor league players and the win-loss record of the big league team are completely independent of one another.

“The decision to promote anyone to Chicago, first of all, is not going to be based upon there being a need in Chicago, or not based upon underperformance of other players in Chicago,” Hahn said Wednesday. “As satisfying as it might be to reward the fans who have endured this rough start by dropping a top prospect in there as a bit of a cookie, to show progress in this process and to make the games perhaps a little more palatable, unfortunately, it just isn’t going to be the motivation. It’s going to be based upon the player having completed every element of his development that we could possibly have at the minor league level.

“There are certain things, as was the case last year with (Yoan) Moncada, that we just can’t replicate in the minor leagues. Speed of the game, the way hitters react to pitchers, the way the pitchers adjust to the hitters, the scrutiny, the grind, those things we can’t replicate. But there is a lot they that can still happen from a developmental standpoint down in the minors, and until the individual player has answered the questions we’ve had for them, they’re going to remain there. They’re going to dictate the schedule, not what’s going on in Chicago.

“Ideally you would like to have them poised for success from the start. We know how challenging it is at this level, we know that development is not linear, so we are prepared for the fact that a guy may struggle in Chicago and need to go back to the minors. … I mean, it happens throughout the game and it certainly not fatal towards a guy’s development or him becoming an impact player. But yes, ideally you want them to come here, be able to establish himself early and have success, and continue to develop.”

Kopech’s promotion has seemed inevitable as he’s gotten off to a very strong start at Triple-A Charlotte. There was a good case to be made that he was the White Sox best pitcher at any level of the organization, majors included, when the team broke camp in Arizona. But as good as Kopech is and appears to be every fifth day, there are still reminders that he has things to improve on. His last start lasted only three innings and 66 pitches.

There are contractual and financial reasons the White Sox could be delaying (and would be smart to delay) Kopech’s debut until later in the season. But even still, the priority has always seemed to be making sure everything has been appropriately developed in the minors. Heck, Kopech is only 22 years old with just nine Triple-A starts under his belt.

“When they’re getting close to getting here, I think it will be pretty obvious to everybody based on their performance, and one day we’ll have an announcement that he’ll be activated tomorrow,” Hahn said. “(Kopech) continues to progress, and important elements of his development are happening down there at Charlotte. Not just the number of changeups he’s throwing or the effectiveness of the changeup, but the stuff you can’t really see in terms of his preparation and his reaction to adversity and how he responds to that in between starts. It’s a process. Not all of it’s obvious to the eyes, not all of it can be picked up from a stat line. We’re definitely pleased with the progress, but there’s work to be done.”

All right, so no surprise Kopech debut this weekend against the Cubs. Well, what about Jimenez, who is pretty much doing everything right down at Double-A Birmingham? Reading a memo from the Department of Accurate Statements, Hahn said: “He’s in a pretty good spot right now.”

So what more is there for Jimenez to accomplish in the minor leagues? There's plenty for him still to experience, according to Hahn.

“I think he’ll be pitched a little bit differently when he gets to Triple-A,” Hahn said. “There’ll be a bit of a more veteran-type staff. Double-A tends to be primarily a prospect level. Lot of guys with real good stuff who are trying to harness that stuff, speaking in general terms. And in Triple-A, you see a few more veteran types who might keep hitters off-balance, get them to expand the zone a little bit more, are a little more on the finesse side of things or at the very least have some more big league experience. Those, they tend to approach or attack hitters a little bit differently.

“I do think he’ll be attacked a little bit differently once he does get to Charlotte, and that’d be beneficial for him.”

And it’s not just the two biggest names of the White Sox rebuild that all this applies to. Seby Zavala, Zack Collins, Dylan Cease, Dane Dunning, Micker Adolfo, Luis Alexander Basabe and Blake Rutherford are all putting up some very good numbers. But that’s not the whole story of their ongoing development or the final determination that they’re ready to advance through the system.

“A lot of it’s the at-bat to at-bat consistency and approach,” Hahn said. “Some of it is playing the game the right way. When a man’s on second and nobody out, are we taking an approach to get the guy over? What type of pitches are they doing damage on? Are they only doing damage on fastballs, or are they only doing damage on off-speed pitches, and what can we do to try to even that out if it’s off-balance?

“Lot of it is preparation and approach, and just making sure each AB is consistent in trying to accomplish what the overall goal for that player is. The guys who are putting up big numbers are probably doing a pretty good job in those categories, it’s just there are things beyond simply the stat line that our development people and our scouts need to see before recommending a promotion.”