On Wednesday, the Minnesota Twins announced they were calling up third baseman Miguel Sano to the Majors, the second time in a matter of weeks that the Twins welcomed one of baseball's top prospects to the big league club. They had already called up outfielder Byron Buxton, who came into the season as the number-two prospect by Baseball America, and now Sano, who was 13th on their preseason list.

After missing all of last season due to an injury, Sano responded with an outstanding season in Double-A, hitting .274/.374/.544 with a 13.3% walk rate (BB%), a weighted on base average (wOBA) of .413, and a weighted runs created (wRC+) of 157. He slugged 15 home runs in 286 plate appearances.

The Twins obviously felt there was no reason to have the 22-year-old slugger visit Triple-A and decided he would be better served helping Minnesota try to stay in the American League Central race. (They are 41-37, five games behind the Kansas City Royals heading into Wednesday night's games.)

Baseball has seen an assembly line of top prospects make The Show this season, and most of them have put up some terrific numbers. But there have been others who experienced the more typical growing pains and were sent back down.

Here is how Baseball America's top prospects heading into 2015 have fared after being called up so far (number indicates preseason Baseball America ranking).

1. Kris Bryant - Chicago Cubs

Bryant's 2.9 fWAR is second-best among all MLB rookies, and while his home run total probably isn't what some were expecting after his spring training bombing blitz, there is room for growth. And that .381 OBP is nice, as is his wRC+ of 135, which shows he's been an above-average run producer. The 23-year-old is still one of the best power hitting prospects in the game, and while his strikeout numbers will probably always be high, those longball totals should shoot up soon as well.

2. Byron Buxton - Minnesota Twins

It's obviously still far too early to say anything definitive about Buxton's start, especially since he's had it cut short already because of a sprained thumb that will keep him out for about a month. It's bad luck for the kid who entered the season as the second-best prospect in baseball.

3. Addison Russell - Chicago Cubs

Russell's 1.4 fWAR ranks sixth among MLB rookies, thanks mainly to being an outstanding defensive second baseman. However, his bat has tailed off recently, and his 31.9% K-rate is a bit worrisome. Still, it's just 60 games, and Russell is one of those talented Cubs position players who will certainly get better as the season wears on.

4. Carlos Correa - Houston Astros

Correa is already the best shortstop in the American League. Yes, he's played just 22 games for Houston, but it's clear as day he is one of the most talented young players to come into the league in a long time. His 1.2 fWAR is already 11th-best among rookies, and fifth-best among AL shortstops. Yes, he's walking in just 3.1% of his plate appearances so far, but he's doing so much damage when he comes to the plate that it hardly matters right now. And Correa has historically been a patient hitter, with anywhere from a 10.6% to 12.3% walk rate in the minors. If baseball wants the best players at the MLB All-Star Game next month, Correa should be there, even after just 22 games.

6. Joey Gallo - Texas Rangers

Gallo got off to a ridiculous start but has been demoted to Triple-A after striking out in a staggering 43.9% of his plate appearances this year. He struck out 43 times since his debut, nine more than any other player in that time. But he did hit five home runs, and that power is legit, with an average homer distance of 440.4 feet, according to ESPN. The 21-year-old had never played above Double-A before being called up, so any expectations other than what he did were probably unrealistic. He's got a bright future as one of the game's premier young sluggers.

8. Joc Pederson - Los Angeles Dodgers

If you needed any more proof that batting average is an over-used stat, Pederson's 2015 should help you see the light. He came into the season as the eighth-best prospect in baseball but is clearly in the lead for National League Rookie of the Year, with an MLB-best 3.6 fWAR among rookies, which also ranks ninth-best in all of baseball. But it shouldn't have come as a shock. Pederson was a 30-30 guy in the minors last year, a pretty impressive feat when you consider minor league seasons are typically only 120-plus games long. His 17.0% walk rate is fantastic and he's just crushing everything he sees, all while playing an above average defensive center field.

9. Francisco Lindor - Cleveland Indians

Lindor has gotten off to a slow start at the plate, but he's only been up with the team for a little over two weeks. The 21-year-old shortstop will never be known as a patient hitter, but was a very good table setter in the minors with plus-speed and excellent defense. In fact, you won't see a better play from a shortstop this year.

GIF: Francisco Lindor with the instant web gem to rob Evan Longoria of a hit. #Indians pic.twitter.com/RWHv6tt8Dj

— Hayden Grove (@H_Grove) July 1, 2015

He'll be okay.

11. Noah Syndergaard - New York Mets

Syndergaard has been terrific since joining the Mets rotation, compiling a 1.4 fWAR in just nine starts, fourth-best among MLB rookie pitchers. His walk-rate is downright filthy, and with an upper 90s heater and knee-buckling curveball and changeup, he has been one of the best rookie starters in the Majors this year.

12. Jorge Soler - Chicago Cubs

Hey, another Cubs player. Who'da thunk it? Now on the 15-day disabled list with an ankle injury, Soler had gotten off to a decent, if unspectacular, start. Like every other young Cubs player, he's had issues with the K, striking out 32.2% of the time so far this year. However, he was walking at a 7.2% clip, and his walk rate in the minors was higher, so it's safe to assume that will inch up a bit the more he sees Major League pitching. He's got a ton of power, but it's been hiding behind a small bush so far this year. However, you get the feeling it's just lying in wait.

15. Carlos Rodon - Chicago White Sox

Yet another gas-thrower, this 22-year-old left-handed Rodon mixes in a devastating slider and a changeup as well to keep hitters off-balance. Control has been an issue so far with Rodon, walking 12.4% of batters with a rather high walks plus hits per inning pitched (WHIP) of 1.64. Still, his 22.0% strikeout rate proves he's got the stuff to be a future ace of the staff.

The Others

The 17th-ranked prospect, catcher Blake Swihart, has been excellent behind the plate in the 40 games he's played since his call-up but has struggled with the bat a bit. He's hitting just .241/.279/.323 with a 63 wRC+. Blue Jays starter Daniel Norris, the 18th-ranked prospect, has a 3.86 ERA in five starts, with a way-too-high WHIP of 1.50 in 23.1 innings. And 19th-ranked prospect, Cubs catcher Kyle Schwarber, was just called up a few days ago, so it's too soon to say anything about him.

Two players further down the preseason prospect list that have done well are Rays outfielder Steven Souza, who came into the season as baseball's 37th-ranked prospect. His batting average is low (.212), but he's slugged 14 homers in 293 plate appearances, with an fWAR of 1.4, tied for sixth-best among rookies. And while he likely won't challenge Pederson or Bryant for the NL Rookie of the Year crown, 56th-ranked prospect Maikel Franco of the Phillies has had an eye-opening season. He led all National League players with 38 hits in June, with a .352 batting average and a 1.039 OPS, blasting 10 homers with 32 RBI and a 1.3 fWAR in just 43 games, tied for ninth-best among first-year players.

The Non-Prospects

And hats off to the outstanding rookies who were not in Baseball America's pre-season Top 50, including San Francisco's Matt Duffy, with the third-highest fWAR among rookies at 2.4. St. Louis' Randal Grichuk is right behind him with a 2.0 fWAR, and Atlanta's Jace Peterson is fifth among rookies with a 1.6 fWAR.

Among pitchers, atta boys go out to San Francisco's Chris Heston, who has a no-hitter under his belt and leads rookie pitchers in fWAR at 1.6. Houston's Lance McCullers and Minnesota's Trevor May are right behind him with a 1.5 fWAR, Cincinnati's Anthony DeSclafani, Toronto's Roberto Osuna, and Tampa's Nate Karns are all having solid rookie seasons as well.