Drafting in baseball has long been an inexact science, but the Giants have had the good fortune of hitting on several players who developed into foundational pieces for some of the best teams in franchise history.

Here’s a look at San Francisco’s Top 5 homegrown Draft picks:

1) Buster Posey
First round, fifth overall, 2008
Catcher Buster Posey was a Freshman All-America shortstop in his first year at Florida State University, but he converted to catcher as a sophomore at the suggestion of one of his coaches. It proved to be a smart move. Despite having no previous catching experience, Posey demonstrated a remarkable aptitude for the position and quickly developed into a plus defender behind the plate. That skill, coupled with his offensive prowess, transformed him into one of the most coveted picks in the country leading up to the 2008 MLB Draft.

Posey, of course, landed with the Giants, a move that launched the most successful era in franchise history. Posey emerged as the cornerstone of the Giants’ three World Series-winning teams in 2010, '12 and '14, marking the club’s first championship titles since the organization moved west in 1958.

Over his first decade in San Francisco, Posey established himself as one of the most decorated players in Giants history. He captured the 2010 National League Rookie of the Year Award and the '12 NL MVP Award. His credentials also include six All-Star selections, four Silver Slugger Awards, a Gold Glove Award and the '12 NL batting title.

2) Will Clark
First round, second overall, 1985
The Brewers opened the 1985 Draft -- one of the best in baseball history -- by selecting B.J. Surhoff. The Giants followed by drafting Will Clark, a sweet-swinging first baseman out of Mississippi State University who helped spark one of the biggest turnarounds in franchise history. San Francisco lost 96 games in '84 and 100 in '85, but its fortunes began to change when Clark debuted in '86. In his first career at-bat in the Majors, Clark homered off Hall of Famer Nolan Ryan at the Astrodome, signaling the arrival of “The Thrill.”

Clark, who led the Giants to the NL West title in 1987 and a World Series appearance in '89, batted .299 with 176 home runs and 709 RBIs over eight seasons in San Francisco. He earned five of his six career All-Star selections with the Giants, along with two Silver Slugger Awards and one Gold Glove Award. Clark delivered one of his finest seasons in '89, when he hit .333 with 23 home runs and 111 RBIs and finished second in the NL MVP voting, behind only teammate Kevin Mitchell. Still, Clark captured MVP honors in the '89 NL Championship Series after batting .650 with two home runs and eight RBIs to help the Giants beat the Cubs in five games.

3) Matt Williams
First round, third overall, 1986
Third baseman Matt Williams debuted with the Giants in 1987 at age 21, only a year out of UNLV, but he struggled to establish himself over his first three years in the Majors. He finally broke through in '90, when he hit .277 with 33 home runs and an NL-high 122 RBIs in his first full season as a big leaguer.

Williams never looked back, earning four All-Star selections and three Gold Glove Awards over his 10-year tenure in San Francisco. He topped the 30-home run mark four times with the Giants, including a career-high 43 home runs in 1994. That season was cut short by a players strike, robbing him of the opportunity to chase Roger Maris’ single-season home run record (61). He finished second in NL MVP voting to the Astros’ Jeff Bagwell.

Williams spent two more seasons with the Giants before being dealt to the Indians in exchange for Jeff Kent, Julian Tavárez and José Vizcaíno in 1996. His 247 home runs with the Giants rank fourth in San Francisco history, behind only Barry Bonds (586), Willie McCovey (469) and Willie Mays (459).

4) Madison Bumgarner
First round, 10th overall, 2007
Pitcher Madison Bumgarner spent the first 11 years of his career with the Giants, going 119-92 with a 3.13 ERA while earning four All-Star nods and two Silver Slugger Awards. He reserved his best work for October, when he established himself as one of the greatest postseason pitchers in baseball history during the Giants’ run of three World Series championships in five seasons from 2010-14.

The fiery left-hander out of South Caldwell High School in Hudson, N.C., carried his club over the finish line in 2014, logging a 0.43 ERA over 21 innings against the Royals and converting a five-inning save in Game 7 to close out the club’s third title in five years. Bumgarner’s historic performance made him the obvious choice for World Series MVP, marking the first time the prize had been awarded to a Giants pitcher.

5) Robby Thompson
First round, second overall, 1983 (secondary phase)
Robby Thompson spent his entire 11-year career with the Giants, making two All-Star teams and winning the 1993 NL Gold Glove Award. The undersized second baseman reached the Majors in '86 despite not having played a single game above Double-A and quickly became a fan favorite because of his grit and scrappiness on the field. Thompson batted .271 with seven home runs and 47 RBIs that year, finishing second in NL Rookie of the Year voting to the Cardinals’ Todd Worrell.

Thompson enjoyed a career year in 1993, when he hit .312 with a 136 OPS+ and 19 home runs to earn the NL Silver Slugger Award at second base. When he retired following the '96 season, Thompson was the all-time leader among San Francisco second basemen in most categories, including games played (1,264), hits (1,187), doubles (238), home runs (119) and RBIs (458).

Honorable mentions
OF Jack Clark, 13th round, 1973
RHP Matt Cain, first round, 25th overall, 2002
SS Brandon Crawford, fourth round, 2008
1B Brandon Belt, fifth round, 2009
RHP Tim Lincecum, first round, 10th overall, 2006