NFL Draft: 10 Biggest Busts in Draft History

History proves the NFL draft is not an exact science—for every Pro-Bowler, there are just as many players who do not live up to expectations. 

The gamble in drafting players lead Colts president Bill Polian to once call the draft a "crapshoot" (Mike Bruton, Philadelphia Inquirer). 

And this quote is coming from one of the better drafting teams in the NFL.

While it's true that not all first rounders turn out to be All-Pros, some draft decisions are more catastrophic than others. 

Here are the 10 biggest all-time busts in the history of the NFL Draft.

1. Washington State QB Ryan Leaf

Jeff Gross/Getty Images

24 Dec 2000: Quarterback Ryan Leaf #16 of the San Diego Chargers looks to pass the ball during the game against the Pittsburgh Steelers at Qualcomm Stadium in San Diego, California. The Steelers defeated the Chargers 34-21.Mandatory Credit: Jeff Gross /A

Leaf and Peyton Manning were the consensus one and two QB's in the 1998 NFL, but their careers could not have been more different. 

Leaf posted a QB rating of only 50 for his career, and his touchdown to interception ratio was an abysmal 14-36. 

Leaf was also very immature, having two on camera altercations with San Diego reporters.  

Safety Rodney Harrison, Leaf's teammate at the time, called playing with Leaf, "a nightmare you can't even imagine."

He retired from the league in 2002, and has since been a coach at West Texas A&M.  He is now living in Canada, working as a business development manager for a travel company.

2. LSU QB JaMarcus Russell

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DENVER - DECEMBER 20: Quarterback JaMarcus Russell #2 of the Oakland Raiders drops back to pass against the Denver Broncos in the fourth quarter at Invesco Field at Mile High on December 20, 2009 in Denver, Colorado. The Raiders defeated the Broncos 20-1

Russell is another example in a long list of draft day blunders by Raiders owner Al Davis.

Weight concerns dogged him his entire career, with one report saying he arrived at training camp weighing 300 lbs.

At that weight, Russell would be better served playing offensive line rather than QB. 

Russell had a career touchdown to interception ratio of 18 to 23, and never completed more than 55 percent of his passes in a season.  

The Raiders cut the former number one overall pick after just three years in the league—the shortest tenure of a QB taken number one. 

He remains unsigned, but is looking to rejoin the NFL.  

3. MSU OT Tony Mandarich

George Rose/Getty Images

ANAHEIM, CA - SEPTEMBER 24: Tony Mandarich #77 of the Green Bay Packers looks on during the game against the Los Angeles Rams at Anaheim Stadium on September 24, 1989 in Anaheim, California. The Rams won 41-38. (Photo by George Rose/Getty Images)

No one could have foreseen Mandarich being a bust. 

Nicknamed "the incredible bulk" coming out of college, Mandarich was an unheard of athlete at the tackle position.

Not surprisingly, he dodged questions about steroid use his entire career. 

Despite his enormous size and strength, he spent most of his time in Green Bay as a special teams player. 

Three years into his rookie contract, he was cut by the Packers. 

While he never lived up to expectations, Mandarich did open the eyes of college and pro teams to the importance of drug testing, and the current testing rules of the league can be attributed largely to Mandarich.  

4. MSU WR Charles Rogers

Doug Benc/Getty Images

TAMPA, FL - OCTOBER 2: Wide receiver Charles Rogers #80 of the Detroit Lions catches a pass in the fourth quarter against the Tampa Bay Buccaneers on October 2, 2005 at Raymond James Stadium in Tampa, Florida. The Buccaneers defeated the Lions 17-13. (Ph

Rogers was supposed to be the next Randy Moss, but injuries and drugs derailed his once promising career. 

He was selected second overall in the 2003 draft, but suffered season ending injuries his first two years in Detroit.

After being suspended four games in 2005 for failing a drug test, he fell out of favor with Detroit management, and was released in 2006.

Because of rumors of prior drug history at MSU, Roger's contract contained a clause forcing him to return his signing bonus to the Lions should he ever received a drug related offense. 

He was forced to pay the Lions $6.1 million of his $9.1 million signing bonus.  

Since being released, he has been arrested three times and is currently serving a jail sentence.

5. Oregon QB Akili Smith

Tom Pidgeon/Getty Images

CINCINNATI - OCTOBER 13: Akili Smith #11 of the Cincinnati Bengals before a game against the Pittsburgh Steelers at Paul Brown Stadium on October 13, 2002 in Cincinnati, Ohio. The Steelers beat the Bengals 34-7. (Photo by Tom Pidgeon/Getty Images)

Smith had only 11 career starts in college, so the Bengals took quite a risk selecting him third overall in the 1999 NFL Draft. 

Smith started only 17 games in four seasons with the Bengals before being cut in 2002.  He has been out of the league since 2005.  

He tried unsuccessfully to transition to the CFL, lasting only two games before being released by the Calgary Stampeders. 

He is now working with Jeff Tedford (his offensive coordinator at Oregon) as an offensive assistant at the University of California.  

6. OSU DE Vernon Gholston

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EAST RUTHERFORD, NJ - AUGUST 16: Vernon Gholston #56 of the New York Jets takes down Mike Sellers #45 of the Washington Redskins in a pre-season NFL game at Giants Stadium, August 16, 2008 in East Rutherford, New Jersey. (Photo by Jeff Zelevansky/Getty

Gholston set the OSU record for sacks in a season with 14.5, and his long arms and speed allowed him to play either DE or LB in the NFL. 

But even under the tutelage of defensive genius Rex Ryan, Gholston could never establish himself as a pass rusher, starting only five games in three years for the Jets, finishing with zero career sacks. 

Gholston's complete lack of production is almost unheard of for a pick that high, and is equally perplexing because Gholston (by all accounts) is a hard worker and good teammate.  

The Jets cut him following the 2010 season and he will now have to look for another team to give him a chance.  

7. West Virginia CB Adam "Pacman" Jones

Stephen Dunn/Getty Images

HOUSTON - DECEMBER 10: Pacman Jones #32 of the Tennessee Titans returns the opening kickoff of the overtime period against the Houston Texans on December 10, 2006 at Reliant Stadium in Houston, Texas. The Titans won 26-20 in overtime. (Photo by Stephen

Much like Rogers, Pacman is another example of a player whose off-field issues derailed his career.

The talent was always there for Pacman, but his focus was never where it needed to be. 

His NFL tenure got off to a rocky start; he was arrested before the start of his rookie season for assault stemming from a nightclub altercation.  

A successful playing career followed, as Jones had three punt return touchdowns in the 2006 season, but during the offseason, he was arrested again for another altercation at a strip club. 

New commissioner Roger Goodell came down hard on Jones, suspending him an entire year.  The Cowboys gave Jones another chance in the 2008 season, but he was cut for more off-field issues. 

If only Jones could have stayed out of those strip clubs, who knows how his career would have played out. 

He currently plays for the Bengals, but missed last season due to a neck injury.  

8. Penn State RB Blair Thomas

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7 Oct 1990: Running back Blair Thomas of the New York Jets moves the ball during a game against the Miami Dolphins at Joe Robbie Stadium in Miami, Florida. The Dolphins won the game, 20-16. Mandatory Credit: Tim DeFrisco /Allsport

Thomas is perhaps the highest drafted RB bust in NFL history.

Thomas was the Senior Bowl MVP and member of Penn State's 1986 National Championship team, and was rewarded by being the second overall selection in the 1990 NFL Draft. 

After an impressive rookie season, where Thomas averaged five yards a carry, he was promoted to starter, but never panned out. 

He had only seven rushing touchdowns in his six year career, and was released by the Jets after the 1993 season. 

Unsuccessful stints with the Patriots, Cowboys, and Panthers followed.  He has been out of the league since 1995.  

9. Washington DE Steve Emtman

Scott Halleran/Getty Images

4 Oct 1992: Defensive lineman Steve Emtman of the Indianapolis Colts looks on during a game against the Tampa Bay Buccaneers at Tampa Stadium in Tampa, Florida. The Colts won the game, 24-14. Mandatory Credit: Scott Halleran /Allsport

Emtman could never establish himself as a player because of injuries. 

He started just 19 games in his six year career.  His first three seasons all ended on injured reserve. 

He retired in 1997 at the ripe old age of 27, finishing his NFL career with just eight sacks. 

He now works as a real estate developer in his home state of Washington.  

10. Penn State RB Curtis Enis

Jonathan Daniel/Getty Images

17 Sep 2000: A close up of Curtis Enis #44 of the Chicago Bears as he looks on from the sidelines during the game against the New York Giants at Soldier Field in Chicago, Illinois. The Giants defeated the Bears 14-7.Mandatory Credit: Jonathan Daniel /Al

Enis is another Nittany Lion RB who did not fare well in the NFL. 

Taken with the fifth pick in the 1998 NFL draft, Enis only lasted three years in the NFL, with an unimpressive 3.3 yards per carry average.  Ball security was an issue, as he lost four fumbles during his second NFL season.

He retired from the NFL in 2001 due to a degenerative condition in his left knee.

He now works as a high school football coach.