This is not a list players would like to see their names on.
NFL training camps and preseason games do more than just ready players for the grind of the regular season. They also weed out the haves from the have-nots—those who have the talent and skill to make an impact on a team all season long and those who don't.
In an ideal world, every player who takes to the practice field this summer would be a prototype at his position, with all errors corrected quickly and no one falling behind.
However, that's not how it works. For many reasons—a change in the offensive or defensive system, a shift in position or simple lack of ability—there are players around the league who disappoint during camps and the preseason.
Here are a few who are standing out for all the wrong reasons this summer.
When the Miami Dolphins lost out in the bidding war to retain free-agent left tackle Jake Long, they had to find another solution. Instead of taking on a rookie in April's draft, they decided to move Jonathan Martin from right to left tackle and pick up Tyson Clabo to replace Martin on the right.
So far, the experiment isn't paying off. Martin has been manhandled in practice, primarily by pass-rushers Dion Jordan and Olivier Vernon, and he is looking worse in pass protection at the left side of the line than he did at the right. Though well-suited for run-blocking, Martin seems overwhelmed by his new assignment.
As Bleacher Report's Erik Frenz pointed out, Martin's five outings at left tackle last season didn't go well, allowing pressures on 10.32 percent of his snaps. He didn't look good in the team's first two preseason games, either.
Protecting the quarterback is one of the most important jobs in the NFL, and when Martin, who has that responsibility more than any other player, is already faltering in training camp and the preseason, the regular season might not be the most comfortable time for Ryan Tannehill.
San Francisco 49ers wide receiver A.J. Jenkins is starting his second year in the league, but he doesn't seem to be catching on any better, according to reports out of training camp.
Jenkins, who didn't catch a single pass last season, is struggling to pull down the football in practices. He was held without a reception in practice earlier in the week, according to Matt Maiocco of Comcast SportsNet Bay Area, and now his spot on the roster is in jeopardy.
Per Rotoworld, "49ers WR A.J. Jenkins has been targeted five times through two preseason games, and the results are four incompletions, two interceptions, one catch for 11 yards, and a fumble lost."
Despite the 49ers' issues at wide receiver, however, the team seems open to the idea of cutting the first-round draft pick, according to both Tim Kawakami of the San Jose Mercury News and CBS Sports' Jason LaCanfora, who described Jenkins as "beyond frustrating."
When a first-round draft pick is on the roster bubble in just his second season in the NFL, it's a clear indication that training camp isn't going well. Such is the case with Jenkins, who, barring a miraculous turnaround, may find himself out of San Francisco despite the team's issues at receiver.
The Philadelphia Eagles signed free-agent cornerback Cary Williams to a three-year, $17 million deal in the spring, but they have yet to see a return on their investment.
First, Williams skipped out on OTAs to check on the construction of his house, get dental work done and watch his daughter's dance recital. Then, when he finally joined his new team, he promptly injured his hamstring and has missed most of training camp.
Further, when he did return to practice last week—before injuring the hamstring again—he chose to pick a fight with New England Patriots receiver Aaron Dobson during a joint scrimmage prior to their Week 1 preseason game—all in the name of trying to make the Eagles defense seem more tough.
Williams, who was Pro Football Focus' 68th-ranked cornerback for 2012 (subscription required) when he was with the Baltimore Ravens, had four regular-season interceptions last year along with 17 passes defensed. When he plays well, he's an asset. But he did allow 64.4 percent of the passes thrown his way last year to be caught, and he also gave up a team-worst seven touchdowns.
For his price, as well as the fact that Williams has spent more time off the practice field than on—combined with his OTAs absences and the fight with Dobson—Williams has certainly had a disappointing summer.
Though New York Giants running back Andre Brown seemed to be the best choice for the starting job this year—David Wilson is still learning the finer points of pass protection—he's presently sharing duties, according to the Giants' depth chart. Wilson and Brown have both been named starters.
This may be due to the fact that the two men each have one true season of NFL experience—Wilson is a second-year player, while Brown has been in the league since 2010 but didn't make an impact until last year—but it may also be Brown's lost fumble in the Giants' Week 1 preseason win over the Pittsburgh Steelers.
Brown didn't land in coach Tom Coughlin's doghouse like Wilson did after a fumble last year, but the misstep opens a path for Wilson to be the one getting the most carries this season.
Another fumble, and Brown's esteem in his coach's eyes could continue to fall. The Giants didn't have much of a run game in that Week 1 win, so Brown's reliability is necessary for the team to have a balanced offense.
Even before training camps and the preseason began, things weren't going so well for Jacksonville Jaguars receiver Justin Blackmon, who was slapped with a four-game suspension in April for a violation of the NFL's substance-abuse policy.
In the team's first preseason game against the Miami Dolphins, Blackmon got into a sideline shouting match with Dolphins cornerback Nolan Carroll. Blackmon's teammate, running back Maurice Jones-Drew, had to escort Blackmon to the locker room to cool off. During the altercation with Carroll, Blackmon also exchanged words with a fellow Jaguar, defensive end Jason Babin.
The Jaguars need Blackmon on the field if QB Blaine Gabbert has any chance for success this year. Surgery is one thing, but arguing his way off of the sideline and picking up a four-game suspension isn't a good start to the season for Blackmon.
Detroit Lions safety Louis Delmas missed eight games last year (after a knee injury required surgery) and 15 total over the past four seasons. However, the Lions, who desperately need talent in their secondary, chose to re-sign Delmas to a two-year, $9.465 million deal this spring—a deal that has a lot of incentives tied up in playing time, thankfully.
Though Delmas sat out minicamps and OTAs, head coach Jim Schwartz believed that the safety would be ready for training camp, where the plan was to give him adequate rest days in order to preserve his knees. He participated in training camp for about a week at the end of July, but then missed additional days when his knee again began giving him discomfort.
A few days later, Delmas said he was feeling better than he had in a long time. But he's still limited in practices and hasn't made a single appearance in Detroit's two preseason games, and he won't likely play a snap until the regular season.
While it's hard to fault Delmas considering his disappointing summer is related not to performance issues but to injury, there's a saying in the NFL that "the best ability is availability," and Delmas has yet to demonstrate that. The Lions hoped that Delmas would be healthy enough to fully practice by now, but it hasn't turned out that way.
Hopefully his knee will be ready for the regular season, though it's hard to imagine Delmas playing a full 16 games—something he's never done.
It was a given all eyes would be on the New York Jets, as their quarterbacks, 2012 starter Mark Sanchez and 2013 draft pick Geno Smith, battled it out for the right to open the regular season under center. For the Jets, they likely hoped it was less of a circus, however.
The summer started with Sanchez as the clear front-runner, with head coach Rex Ryan saying in June that were the season to start then, Smith wouldn't be ready to take on the job. Smith improved over the course of training camp, however, and through seven practices and a scrimmage had no interceptions to Sanchez's four—though he did take 12 sacks compared to nine for Sanchez.
Sanchez was the Jets starter in their first preseason game against the New York Jets, promptly throwing an interception before calming down, completing 10 of 13 passes for 125 yards and a touchdown. It seemed like the competition was wide open. However, Smith's showing didn't last long, completing six of his seven passes for 47 yards before exiting with an ankle injury.
Though Smith has missed no practice time because of the ankle, it's affected how he's performed. Earlier this week, Smith had a bad day of practice—described by Ryan as "brutal"—throwing four interceptions, most likely because his ankle isn't close to healthy. Therefore, the Jets named Sanchez as the starter for the team's second preseason game.
This battle will eventually have a winner, but the Jets may ultimately have won nothing by having to choose between these two quarterbacks to begin with.
UPDATE: 5:30 p.m. ET
According to a tweet from NFL Network's Albert Breer, Smith will not be playing in the Jets' preseason game against the Jacksonville Jaguars on Saturday night.