The San Francisco Giants have used the farm system to bolster the big league squad in each of the last three seasons, which is why it's important to keep a close eye on the team's minor league affiliates. 

In 2010, the team brought up top prospects Madison Bumgarner and Buster Posey to help bring the organization its first championship since moving to San Francisco.

Bumgarner replaced fifth starter Todd Wellemeyer in the rotation and put up a 3.00 ERA over 18 starts before throwing eight shutout innings in Game 4 of the World Series. Posey replaced Bengie Molina behind the plate and hit .305/.357/.505 with 18 home runs to earn Rookie of the Year honors.

Hi-res-165850408_crop_exact Is there a prospect in the farm system who can provide the Giants a lift like Posey once did?
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In 2011, the Giants traded top prospect Zack Wheeler to the Mets for Carlos Beltran, who hit .323/.369/.551 with seven home runs for the Giants. However, the acquisition of Beltran ultimately wasn't enough to make up for the loss of Posey to a season-ending injury, as the Giants fell short of the playoffs.

Last year, prospects Brandon Crawford and Brandon Belt established themselves as everyday players to help the Giants win their second World Series championship in three years. Crawford established himself as a Gold Glove candidate with his slick work in the field, and Belt put up a .781 OPS while also flashing the leather at first base. 

Additionally, general manager Brian Sabean used the farm system to acquire Marco Scutaro and Hunter Pence in midseason trades last year. Scutaro hit .362 for the Giants after the trade and won NLCS MVP honors on the Giants' road to the championship. Pence didn't hit as well as Scutaro, but he delivered several clutch hits down the stretch and key motivational speeches throughout the playoffs.

The Giants' four full-season minor league affiliates got under way along with the big league squad late last week. Time will tell which of the Giants' top prospects will have an impact on the 2013 squad via a promotion or a trade.

Here's how the top 10 league players performed over the first four games of the season last week:

 

1. Kyle Crick: 4.0 IP, 3 H, 1 R, 4 W, 3 K

Crick didn't allow any earned runs in his debut at High-A San Jose, but his lack of control sent him to the showers after just four innings of work. He walked 67 in 111.1 innings last year at Low-A Augusta, so his control bears monitoring this season. Crick has the stuff to pitch at the top of a major league rotation, but he'll have to improve his control to get there.

 

2. Clayton Blackburn: 5.0 IP, 2 H, 0 R, 0 W, 6 K

Blackburn had a more impressive debut at San Jose than his teammate and fellow top prospect Crick. Blackburn doesn't have the same elite stuff as Crick, but his command and control are further ahead at this point. Diamondbacks outfielder Cody Ross was down on the farm rehabbing from injury, and he remarked that Blackburn already has some major league quality stuff:

 

3. Chris Stratton: 5.0 IP, 6 H, 1 R, 1 W,  3 K

The Giants' 2012 first-round pick opened the season at Augusta after having his season cut short when he was struck in the head with a line drive last year. Given that Stratton was a college pitcher taken in the first round, many suspected that he would join Blackburn and Crick at San Jose.

However, the injury appears to have set him back temporarily. He only allowed one run in his first start of the season, but he didn't miss many bats.

Hi-res-6291212_crop_exact Stratton was the Giants' first-round pick out of Mississippi State last year.
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4. Mac Williamson: 6-for-17, 2 HR, 1 2B, 1 3B

Williamson—the Giants' third-round pick last year—pounded the ball in his debut with San Jose. Four of his six hits went for extra bases as he slugged .882 over his first four games. He has the most power of any prospect in the system right now. It isn't hard to imagine him moving quickly through the system in the same way that Belt, Crawford, Posey and Pablo Sandoval once did.

Hi-res-5334600_crop_exact Williamson was the Giants' third-round pick out of Wake Forest last year.
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5. Gary Brown: 4-for-18, 1 3B

Brown had a slow start to the season at Triple-A Fresno. He went just 4-for-18, didn't draw a walk and was caught stealing in his only attempt.

 

6. Joe Panik: 3-for-17

Panik also got off to a slow start at Double-A Richmond. He had three hits—all singles—and didn't draw a walk.

 

7. Martin Agosta: 5 IP, 4 H, 0 R, 0 W, 9 K

Stratton's teammate at Augusta was more impressive in his debut. Agosta—the Giants' second-round pick out of St. Mary's last year—struck out nine of the 18 batters he faced in his first start of 2013. Agosta also struck out 19 of the 50 hitters he faced in his minor league debut last season.

Agosta doesn't rank as highly on some of the other Giants' prospect ranking lists because of his lack of size and lack of a third pitch. Many see him eventually moving from the rotation to the bullpen because of that. However, if Agosta keeps missing bats at his current rate, he's going to stick in the rotation and shoot up the prospect ranking lists in a hurry.

 

8. Chris Heston: 6.0 IP, 7 H, 3 R, 1 W, 9 K

Heston bounced back from a rough spring training with the Giants to earn the victory in his debut at Fresno. He keeps striking out minor league hitters at an impressive rate despite possessing a fastball that rarely cracks 90 mph on the radar gun.

Heston was the Pitcher of the Year at Double-A Richmond last year, where he put up a 2.24 ERA and struck out 135 in 148.2 innings of work.

Hi-res-6378774_crop_exact Heston had a big year at Double-A Richmond last year, but he struggled this spring.
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9. Michael Kickham: 5.0 IP, 4 H, 1 R, 3 W, 6 K

If the Giants need another starter this year, it will likely be a battle between Kickham and Heston for the first call-up. Kickham struck out 137 in 150.2 innings at Richmond last year, but he also walked 75.

Control remained an issue in his debut at Fresno, as he walked three of the 21 hitters he faced. Kickham has better stuff than Heston, but his control clearly still needs polishing. 

Hi-res-162797074_crop_exact Kickham needs to improve his control to get to the big leagues.
Rich Pilling/Getty Images

 

10. Heath Hembree: 2.0 IP, 1 H, 0 R, 1 W, 0 K, 1 SV

Hembree earned his first save of the season on Sunday for Fresno in his second scoreless appearance of the season.

The Giants bullpen has struggled some in the early going. Reliever Jose Mijares doesn't look fully recovered from a spring elbow injury. Thus, it wouldn't be surprising to see Hembree make his big league debut in the near future.

Hi-res-7136324_crop_exact Hembree could be in the big leagues soon.
Jake Roth-USA TODAY Sports

 

Posey, Bumgarner, Belt, Crawford, Sandoval, Matt Cain, Tim Lincecum and Sergio Romo combine to give the Giants arguably the best collection of homegrown talent in the game. Will the Giants add to that impressive crew of graduates from the farm system this season? 

It's too early to establish what the big league club needs this year and which prospects could potentially provide the team with a lift. Hembree is the best bet to give the Giants a shot in the arm at some point.

However, the big arms at the lower levels are sure to be coveted by other teams on the trade market. Will Sabean be gun-shy about dealing away a top pitching prospect like Crick or Blackburn after he was burned in the Wheeler trade?

The season is young, but there's no question that the Giants' minor league system is loaded with arms. The question is whether those arms will eventually help the Giants on the field this year or through what they can bring back on the trade market.

 

All statistics in this article are courtesy of Baseball-Reference.com and MiLB.com.