Cubs fans can whine and fret all they want about the major-league product moving forward at the speed of a frightened turtle. Many of them are doing just that, and who can blame them? When the front-office plan calls for bottomless patience, it’s the fans who are tested most.

Just about anyone with a pulse for baseball would love to see the call-ups of the Cubs’ glittery prospects begin. Good or bad, it would make things more interesting around Wrigley Field than they’ve been in a long time.

So much more interesting.

One might expect the Cubs’ Class AAA golden boys, 22-year-old third baseman Kris Bryant and 21-year-old shortstop Javier Baez, to share in the fans’ impatience. What do guys that age know about patience, anyway?

Turns out, a lot.

‘‘I don’t struggle with it at all,’’ Bryant said. ‘‘I go out there every day and try to play the best that I can for the team that I’m on. Right now it’s the Iowa Cubs, and I’m having a blast with the guys so far.’’

If you were batting .351 with 28 home runs and 75 RBI — those power numbers top anyone’s in the minors or the majors, by the way — entering play Thursday, you’d be having a blast, too. For crying out loud, just imagine some semblance of that production in the middle of the Cubs’ lineup.

‘‘I haven’t thought about it one bit,’’ Bryant said. ‘‘If I’m thinking about that, then it’s taking away from the year I’m having now. My goals are day-to-day goals, things I can achieve on a daily basis, whether it’s taking 50 ground balls at third or having a great [batting-practice] session. I think if you’re putting daily, attainable goals on yourself, getting to the big leagues quicker is kind of a byproduct of that.’’

That’s fair. And wise. Also boring, but entertaining Cubs fans isn’t Bryant’s job — yet.

‘‘My job is to make it hard on the people in charge,’’ he said. ‘‘And that’s what I’m trying to do.’’

Baez hasn’t made as strong a case this season. Despite his 11 homers and 47 RBI entering play Thursday, he was hitting .239. But watch him in just one game, and his talent is beyond obvious. Iowa hitting coach Brian Harper, who was a World Series-winning catcher with the Minnesota Twins, likens Baez to a young Alex Rodriguez.

Geez, think a guy like that might warrant a shot at the next level?

‘‘It feels great to be young and be where I’m at right now,’’ Baez said. ‘‘Hopefully, I’ll get to play in the big leagues and stay up there. But I’m still young, and I know there’s a lot of older guys in Chicago. I’m going to take it easy and day by day, so when the time comes I’m ready.’’

So we wait.

Cubs fans might be tired of having smoke blown up their jerseys, but Harper has some more to add. It’s worth a listen.

‘‘Both of them are unbelievably talented kids,’’ he said. ‘‘Any time you use the word ‘patient’ with a Cubs fan, you’re kind of treading on some bad water. But when you’re talking about developing young players, you do have to have some patience — and that’s regardless of what your big-league team is doing.’’

As Harper sees it, Bryant is destined to be an All-Star. Not bad, right? And there’s that A-Rod comparison with Baez for Cubs fans to keep in their back pockets.

Then again, they’ve heard much of this sort of stuff already. Like it or not, they wait.

Email: sgreenberg@suntimes.com

Twitter: @SLGreenberg