Whether it's due to lack of size, playing at a smaller school, a small playing sample size, injury history, maturity issues or a poor performance at the NFL combine, some draftees drop or are ignored because of a teams' wariness to select them.
Sometimes, teams out-think themselves focusing not only on a player's production on the field, but rather on other factors.
When teams do this sometimes, these questionable picks come back to bite them in their rear.
After setting all kinds of NCAA receiving records, Jerry Rice ran a 4.7 40 at the combine. His lack of speed and the fact that he went to Mississippi Valley State University, a small school, led him to drop to the No. 16 pick. He was the third receiver taken, behind Al Toon and Eddie Brown. Both had respectable careers but nowhere near Rice's.
Even though Tom Brady won 20 out of 25 games as a starter at Michigan, along with two bowl game wins and was an All Big Ten honorable mention, his horrible combine performance and measurements dropped him to the sixth round even.
Former Defensive Player of the Year James Harrison went undrafted after teams feared his lack of size. Going into the 2002 NFL draft, Harrison only measured at 6'0'' and 240 lbs.
Most recently, after being named a two time All-American at Central Michigan and catching 110 balls in his junior year, the undersized 5'10'' Antonio Brown dropped into the sixth round before the Pittsburgh Steelers drafted him with the 195th-overall pick in the 2010 draft.
Since then, he already has been named to his first Pro Bowl.
Every year, a player drops. Here are players in this year's draft that are worth taking a chance on.
Tommy Streeter is a 6'5'', 219-pound wide receiver out of the University of Miami. He was one of the fastest at his position at the combine, with an official 4.40 40 time.
Streeter is still very raw, as he started only one year at Miami. He needs to learn how to run routes better and concentrate more on catching the ball with his hands rather than body.
It appears he is willing to put in the time to improve. In 2011, Streeter won the Nick Chickillo Most Improved Player award.
Last year at Miami, he had 46 receptions for 811 yards and eight TDs, averaging 17.6 yards per catch.
While Streeter posesses ideal size and speed, his lack of experience and amount of production will cost him.
It would be surprising if a team picks him as early as the the third round. However, after five years in the league, it wouldn't surprise me if Streeter is one of the top three receivers in this draft.
San Diego State running back Ronnie Hillman can be a great change-of-pace back for a number of teams. But because he lacks size and played for a smaller school, his skill level will be questioned even after he tied for the second-best 40 time among running backs at this year's combine.
Hillman is 5'8'' and relies on his quickness and vision to find lanes to run through rather than looking for contact, but he doesn't shy away from it.
He is a very hungry player who is an early entry junior in the draft, leaving school early to provide for his two-year-old son. He is also not even 21 years old as of yet.
In his two years at San Diego State, Hillman ran for 1,532 yards with 17 TDs and 1,711 yards with 19 TDs.
He was voted to the All-MWC first team and was named his team's MVP.
Arizona State linebacker Vontaze Burfict was one of the top linebackers headed into the combine, but because he showed up a bit out of shape and performed poorly, his stock has fallen. He couldn't even run the 40 in under five seconds.
He also has some discipline issues with his on-field play since he lets his temper get the best of him, causing him to be called for a lot of personal foul penalties.
When Burfict is able to control his intensity, he is a very productive player. At Arizona State, he was the Pac-10 Defensive Freshman of the Year. He was the consensus best linebacker in the country as a sophomore. And in his junior year, he had 68 tackles, four sacks and an interception.
Pittsburgh Steelers James Harrison had similar maturity problems, but he learned how to harness that rage—well, most of the time—to become a very productive player in the league.
Burfict's fall from grace may have humbled him. All I know is that I wouldn't want to be one of the teams that passed up on him.
Kellen Moore has two strikes against him coming into this year's draft. He lacks the ideal size, and because he played at Boise State, his level of competition might leave a lot to be desired.
But if teams can get past those two facts and focus only on his on-field play, they'll be getting a very accurate quarterback who knows how to win.
During his four-year college career at Boise State, Moore has only lost a total of three times. Quarterbacks coming from smaller schools have done well at the next level in the past. Ben Roethlisberger out of Miami University of Ohio is doing just fine, while Steve McNair out of Alcorn State had a decent career.
Moore is a very accurate passer, as his completion percentage in his senior year was 74.3 percent.
In his senior year, Moore threw for 3,800 yards, 43 touchdowns and nine interceptions on his way to a 124.1 quarterback rating.
His height is comparable to New Orleans Saints quarterback Drew Brees. He does, though, need to add some muscle to his slight frame. Given the time to develop, Moore may transform himself into an actual NFL quarterback.
It still remains to be seen if Moore will get his shot at the next level.
Taylor Thompson is a defensive end out of Southern Methodist University so off the radar that I couldn't even find a proper picture for the beast. That's him above sacking an unlucky QB.
Thompson is a monster at 6'5'' and 282 lbs. who can be a pass-rushing option coming off the bench for any defense.
His game reminds me of the Houston Texans' J.J. Watt, but even if he is a step below Watt, Thompson can be a late-round steal.
In his senior year at SMU, Thompson had 40 tackles, one forced fumble and seven sacks—eight, if SMU's bowl game against Pittsburgh is counted.
No matter how productive Thompson was, teams may balk because the production was at SMU.
Jared Crick has great size at 6'6'' and 285 lbs. He also was very productive at Nebraska, a big school.
In his sophomore year, he had eight sacks, and in his junior year, he had 8.5 sacks.
What will scare teams away from Crick is his injury history. He deals with knee tendinitis. He tore his MCL during spring practice which caused him to miss most of his senior year. He was unable to participate in the bench press at this year's combine due to a torn pectoral muscle.
So when teams draft him, Crick may not be 100 percent healthy for his first season in the league.
If 100 percent healthy, he could have been a second-round lock. But with teams focusing on a drafted player's immediate impact, they will shy away.
In the grand scheme of things, a few games missed at the beginning of a player's career should not cause a player to drop. Especially with modern-day medical advancements.
Justin Bethel has the small school tag on him. But there must be a reason why he was the first player from Presbyterian College to attend the NFL combine.
At the combine, he held his own, ranking similarly to his bigger school counterparts. He even recorded the top vertical jump for all defensive backs.
At 5'11'' and 200 lbs., Bethel is bigger than average safeties. He plays the well against the run and disrupts most receivers.
Similar things were said about another defensive back hailing from Grand Valley State University, another small school.
The Kansas City Chiefs drafted that defensive back after he dropped into the fifth round in the 2008 draft.
During this offseason, that player, Brandon Carr, signed a five-year/$50.1 million deal with the Dallas Cowboys after recording 237 tackles and eight interceptions in his four years in Kansas City.