The NFL's free agency period begins on Wednesday, March 18, when the new league year starts at 4 p.m. After then, teams are free to negotiate with and sign available players.

Teams with cap space often try to upgrade their rosters in free agency. However, sometimes new signings backfire, and teams get stuck with bad contracts and ineffective players.

This offseason, several free agents stick out as potential hazards. They will find their ways onto NFL rosters, but teams should do their homework before forking over millions of dollars to these offensive players.

5. Jordan Reed, TE

Per ESPN's Field Yates, the Washington Redskins released Reed on February 20. The 2013 third round pick missed the entire 2019 regular season after sustaining a concussion during the preseason.

The preseason concussion marked the seventh since Reed started his collegiate career at Florida, per Sports Illustrated. Considering the nature of football, Reed presumably suffered others that either went undocumented or occurred during his youth. After the most recent episode, some wondered if Reed would ever play in the NFL again.

In 2015, Reed reached the peak of his career, recording 87 receptions, 952 yards, and 11 touchdowns. Since then, he's missed 33 games and landed on injured reserve (IR) for three consecutive seasons.

Reed plans to continue playing, according to ESPN's Joh Keim. The former Pro Bowler cleared the NFL's concussion protocol on February 19, meaning he's ready for the 2020 season.

At 29 years old, Reed could still play football for another five or six years. He could return to his 2018 form and produce nearly 43 receiving yards per game. “Could” is the keyword there. Signing Reed on a low-cost, short-term contract makes sense for a team in need of a pass catcher, but who knows if Reed will even make it through the season?

4. A.J. Green, WR

Early in his career, Green rivaled fellow 2011 draft pick, Julio Jones. However, injuries began making a significant impact on Green's career in 2016. He missed six games and finished with fewer than 1,000 receiving yards for the first time.

Green did play all 16 games in 2017, and he made his seventh consecutive Pro Bowl. Unfortunately, a toe injury sent Green to IR after nine games the following season.

This past year, the former fourth overall picked suffered an ankle injury in July that resulted in surgery for some torn ligaments. While the Cincinnati Bengals initially expected Green back before mid-season, he never returned at all. On December 23, the Bengals placed Green on IR.

Green may have been healthy but decided he didn't want to return in 2019, given the state of Cincinnati's team. If he is healthy and capable of returning to Pro Bowl form, Green will be a massive score for a team in free agency. However, there's still the chance the injury bug continues biting Green, and he never plays at an elite level again.

3. Germain Ifedi, RT

The Seattle Seahawks drafted Ifedi with the 31st pick in the 2016 NFL Draft. In four seasons with the team, Ifedi started 60 games and established himself at the right tackle position.

Unlike Green, Ifedi usually stays healthy. He only missed one game over the past three seasons. Ifedi's problem is his play. Despite facing expiring contracts for several key offensive linemen, the Seahawks declined Ifedi's fifth-year rookie option. Seattle, a team desperate for offensive line help, decided Ifedi wasn't good enough to keep around.

At 25-years-old and coming off of his rookie deal, Ifedi wants a long-term, lucrative contract. Last year, the Denver Broncos gave Ja'Wuan James a four-year, $51 million deal. The $12.75 million James makes annually on his contract ranks third among all right tackles.

With La'el Collins, a great right tackle in comparison to Ifedi and James, also signing a deal worth $10 million annually this past season, Ifedi is seeing green. Some team will overpay for the embattled tackle.

2. Melvin Gordon, RB

Gordon opted to holdout for the start of the 2019 NFL season, but he joined the Los Angeles Chargers when a new deal wasn't forthcoming. Gordon wants Todd Gurley-Le'Veon Bell money. However, the Wisconsin product never approached the level of either of those two backs.

During his five seasons with the Chargers, Gordon rushed for more than 1,00 yards once. He never topped the 500 receiving yards mark, and he only averaged more than four yards per carry once. Gordon also missed 13 games during his time in Los Angeles and San Diego.

In his shortened 2019 campaign, Gordon averaged 51 rushing yards per game, the second-lowest average of his career. Despite struggling and missing time, the former Pro Bowler still finished the year with 908 yards from scrimmage and nine total touchdowns. Gordon can produce volume numbers during a season, but his efficiency with the football raises questions.

Four running backs currently make more than $10 million per season on their contracts: Bell, Ezekiel Elliott, Gurley, and David Johnson. Of those players, only Elliott played at an elite level this past season. With Gordon (26) approaching the age where players like Johnson, Alfred Morris, and DeMarco Murray flamed out, teams should strongly consider withholding a massive contract.

1. Quarterbacks

On one end of the free agent quarterback spectrum, there's Marcus Mariota and Jameis Winston. Over the past three seasons, Mariota has thrown 31 touchdowns and 25 interceptions. The Tennessee Titans benched him after six games in 2019.

While Winston started all 16 games for the Tampa Bay Buccaneers in 2019, the team did bench him repeatedly in 2018. Winston led the NFL in passing yards this past season, but he also tossed 33 touchdowns to 30 interceptions.

At the other end of the spectrum is a handful of veterans, including Tom Brady and Philip Rivers. While Brady still played exceptionally well in 2019, he posted his lowest quarterback rating since 2013. How much longer can the 42-year-old play? Rivers showed more signs of aging. The eight-time Pro Bowler threw for 23 touchdowns and 20 interceptions this past season.

Teddy Bridgewater and Ryan Tannehill fall somewhere in the middle. Bridgewater went 5-0 in place of Drew Brees when the veteran got injured last season. Tannehill made ten starts, took the Titans to the playoffs, and won Comeback Player of the Year. However, no one knows if Bridgewater and Tannehill can duplicate their successes in the long run.

Since the end of the 2015 season, Bridgewater has only started six games. His five-game sample with the successful New Orleans Saints should not get blown out of proportion. As for Tannehill, he thrived alongside the league's leading rusher. It's unlikely he will find such a talented running mate again, unless Tennessee retains him and Derrick Henry.

This offseason offers plenty of options for the NFL's quarterback-needy teams. However, most of the quarterbacks come with serious concerns. Organizations should think twice before breaking the bank on a new signal-caller.