Not so long ago, Yoan Moncada was MLB's next big thing.

Now, with the 2019 exhibition slate about to commence, the Chicago White Sox infielder needs to prove he isn't the next big bust.

Last season was rough for Moncada, and that's stating it kindly. He struck out 217 times—more than any other hitter (or, more accurately, more than any other swinger).

He led all second basemen with 21 errors and frequently appeared inept in the field despite his athleticism and five-tool potential.

He hit .235 with a .315 on-base percentage in 149 games, which is...let's check the math...not great.

Even his teammate and fellow Cuban, Jose Abreu, sounded a cautionary note.

"I think sometimes you talk and you create a bigger expectation, and that can create something that is not accurate," Abreu said through an interpreter, per Steve Greenberg of the Chicago Sun-Times. "But we all know the talent that he has."

Moncada is undeniably talented. He's tantalized the baseball world with 30-30 potential since the Boston Red Sox signed him on the international market at age 19 to a $63 million deal in February 2015.

That's a lot of coin to commit to an unproven teenager, but it seemed like a wise idea given his pedigree.

The Red Sox made good on their money in December 2016 by turning Moncada, fireballer Michael Kopech (who will miss 2019 after undergoing Tommy John surgery) and two other prospects into Chris Sale.

At the time, the ChiSox were trading an ace with three years remaining on an affordable, team-friendly contract.

Sale helped the Red Sox win a title in 2018. Moncada has been an enigma with increasingly troubling, bust-evoking tendencies for Chicago.

Yeah...we uttered the "b" word. Now, for the caveat: Moncada is 23 years old. It's too early to apply that label, drop the proverbial mic and walk away.

A lot of intriguing players his age (and older) have yet to play a full MLB season or even sip a cup of coffee at the highest level.

Yet, Moncada was supposed to be on the fast track, a nascent star who would lead the White Sox's budding rebuild.

Instead, he collected K's like they were going out of style, failed to get on base at anything approaching a decent clip, didn't flash eye-opening power and kicked the ball around the field like he was playing in the Premier League.

Was it the burden of being a touted blue chip? Did he succumb to the pressure of expectations?

Nope, if you ask him.

"The weight didn't affect me last year, the weight of being the top prospect," Moncada said, per Phil Thompson of the Chicago Tribune. "I just don't think that affected me at all. I think that this year is going to be a much better year, and I'm just ready for it."

Give the young man points for optimism. Allow for the possibility he'll shine in 2019.

Remember, however, there are footsteps behind him.

The White Sox have other impressive players rising through their system, including outfielder Eloy Jimenez. Moncada could be squeezed out of an infield depth chart that features shortstop Tim Anderson and third baseman Yolmer Sanchez. 

The White Sox's persistent linkage to superstar infielder and free agent Manny Machado doesn't indicate a high degree of faith in Moncada. At least, it suggests Chicago is keeping its options wide open. 

No prospect enjoys too much time in the limelight. Either he seizes it, or it's gone. Poof. The numbers come or they don't. The promise materializes...or it doesn't.

Moncada is officially no longer the next big thing. Now, he's at risk of becoming the next big bust.

Things can change in an instant.

All statistics courtesy of Baseball Reference.