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It’s quickly becoming clear why the Boston Red Sox shelled out big bucks last month to sign Cuban outfielder Rusney Castillo.

Castillo connected for his first major league home run in the third inning of Thursday’s 11-1 win over the Tampa Bay Rays, blasting a three-run shot into the seats above the Green Monster in left-center field.

He has continued to showcase his immense potential in the first two games of the weekend series against the rival New York Yankees, going 5-for-6 with a home run and two RBI through Saturday. 

The Red Sox made Castillo the highest-paid Cuban player in baseball history last month, signing the 27-year-old outfielder to a seven-year, $72.5 million contract through the 2020 season.

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This year’s September call-ups’ brief taste of the major leagues might be coming to an end, but it goes without saying that their futures are increasingly bright.

For the better part of the last month, we’ve been highlighting the top call-ups across baseball, whether it be breaking down their early returns in the major leagues or their potential impact on the playoff races.

Today, however, we’re going to look at the very best September call-ups—specifically, prospects that appeared in our recent end-of-year top 100 prospect rankings—by assigning grades for each player’s overall season while also considering how their performances might affect their respective 2015 outlooks.

With all that being said, here are the grades and projections for Major League Baseball’s top September call-ups.

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For the second straight year, the Los Angeles Dodgers are National League West champions.

Led by another strong performance from probable NL Cy Young Award winner and legitimate MVP candidate Clayton Kershaw, the Dodgers trounced the San Francisco Giants 9-1 in front of a sold-out Dodger Stadium to secure home-field advantage in the NLDS.

Though it wasn’t his sharpest outing, Kershaw allowed just one run on eight hits over eight innings in his final start of the regular season, striking out 11 batters without issuing a walk. The win was the left-hander’s 21st of the season, matching his career high from 2011, and he reached the mark in just his 27th start.

Kershaw also helped his cause by going 1-for-2 with an RBI triple, and he made a potentially game-saving play with no outs in the third inning when he fielded a hard-hit, comeback ground ball behind his back to prevent at least one run from scoring.

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Over the last month, Prospect Pipeline has looked at the top prospects for each position at every minor league level and every team’s prospect of the year. We even went so far as to re-rank all 30 farm systems.

But now it’s the time you’ve all been waiting for: an updated ranking of baseball’s top 100 prospects.

For the most part, the placement of the top 25 players is unchanged compared to our most recent update. However, there were numerous prospects (no spoilers!) that shot up the rankings over the course of the season, and many more have entered the ranks in the wake of this year’s amateur draft.

As is the case with all my rankings, any player who’s accrued 130 at-bats or 50 innings in the major leagues no longer qualifies as a prospect. Additionally, I don’t treat international free agents as true prospects, because there’s no benefit in comparing a 26-year-old Cuban player to an 18-year-old draft pick until they log significant stateside experience.

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It will be several years until most of the 2014 draft picks are ready for the major leagues, but that doesn't mean we can’t get excited about the professional debuts of some of baseball’s brightest young players.

Thanks to an accelerated signing deadline in mid-July that was ushered in in 2012 as part of the new collective bargaining agreement—it used to be mid-August—draft picks are now encouraged to quickly begin their professional careers.

For some prospects, signing early gives them a head start on their development as well as the potential to debut in the major leagues ahead of schedule. At the very least, the half-season of experience this summer should improve their chances of receiving aggressive promotions to begin the following season.

Here’s a look at 2014 draft picks who already turned heads in their professional debuts.

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It hasn't even been three weeks since rosters expanded and teams announced their September call-ups, but some of baseball’s top prospects have already made a splash during their short time in the major leagues.

Hitters such as Cory Spangenberg (San Diego Padres), Maikel Franco (Philadelphia Phillies) and Joc Pederson (Los Angeles Dodgers) made immediate impacts with their respective teams to begin the month, but all three players have since cooled down and, in some cases, have had their playing time reduced. 

Beyond that, many of the top pitching-prospect call-ups have opened eyes facing big league hitters for the first time.

The 21-year-old left-handers, Daniel Norris (Toronto Blue Jays) and Brandon Finnegan (Kansas City Royals), both have pitched well in the heat of a playoff race, which is remarkable, considering Norris began the season in the High-A Florida State League, while Finnegan took the mound every Friday night for Texas Christian University.

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As we put a final bow on the 2014 minor league season, it is a great time to look at the state of the farm systems.

Many of baseball’s top-ranked preseason prospects debuted in the major leagues this season, with promising young hitters such as Oscar Taveras, Javier Baez, Gregory Polanco, George Springer and Joc Pederson each receiving his first taste of baseball’s highest level.

When it comes to impact prospects such as Taveras, Baez or Springer graduating to the major leagues, there’s inevitably a glaring hole left down on the farm.

But which teams are best prepared to replace their top prospects with a new wave of young talent?

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The minor league season may be over, sadly, but our process of rolling out end-of-season awards is just beginning.

Having already looked at the top prospects at each level by position as well as each team’s biggest disappointment, it’s now time to highlight the stars from each organization.

Because so many players' respective performances resulted in promotions to a higher level during the season—in some cases to the major leagues—we determined that pitchers needed at least 100 innings and hitters 450 plate appearances to qualify for this list, thus eliminating any potential concerns about small sample sizes. Along those same lines, we tried to avoid players who received significant playing time in the major leagues, though exceptions were made in some cases.

With all that being said, here is each team’s Prospect of the Year for 2014.

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And just like that, Giancarlo Stanton’s MVP-caliber season came to a tragic end.

Batting in the fifth inning of Thursday’s game against Milwaukee, Stanton was struck flush in the left cheek by an 88 mph fastball from right-hander Mike Fiers. The two-time All-Star fell to the ground immediately, clutching the left side of his helmet as blood streamed off his face.

After lying at home plate motionless—he did kick his foot while writhing in pain—for what seemed like an eternity, Stanton was transported off the field on an ambulance cart and immediately taken to the hospital.

The 24-year-old required stitches for facial lacerations and suffered multiple facial fractures as well as dental damage, per Yahoo Sports’ Jeff Passan on TwitterPassan also noted that Stanton still has a tooth lodged in his cheek and a hole in his lip so big the “doc’s index finger fit in it.”

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With September call-ups out of the way and the minor league playoffs winding down, it’s time to reflect on each organization’s minor league season.

Earlier this week we broke down the season’s top players from each level by position, offering an indirect look at baseball’s best prospects. Today, however, we’re taking a different approach by analyzing each club’s most disappointing prospect from the 2014 season.

To be clear, a prospect that qualifies as a “disappointment,” is one that struggled to live up to his preseason hype—meaning he likely was ranked or touted as one of his team’s better prospects headed into the season—and failed to progress from a developmental standpoint. It's also worth mentioning that labeling a prospect as a “disappointment” based on one season does not mean he’s a bust.

While statistics served as the primary source for determining which players to include in the article, we also considered things such as injuries, park factors and strength of competition.