A different set of players faces a crossroads or has something to prove every year for a variety of reasons. The most common reasons are related to age, contract or salary-cap concerns, injury, poor performance or off-the-field issues.

It's hard to believe now but a couple of injury-plagued seasons led to speculation in 2014 that the Patriots might not pick up the 2016-through-2019 option years for tight end Rob Gronkowski if the pattern continued. Gronkowski ended the speculation by earning All-Pro honors in 2014 after leading NFL tight ends in receiving yards and touchdown receptions.

Quarterback Robert Griffin III is the flip side of the crossroads equation. The 2012 Offensive Rookie of the Year had seemingly found a good situation with the Browns in 2016 in an attempt to resurrect his career after losing his starting job to Kirk Cousins. Griffin fracturing a bone in his left shoulder during his Cleveland debut derailed his season. He was out of football last year after the Browns released him. Griffin signed with the Ravens this offseason but may need a strong preseason to make the team.

Below are 12 players to keep an eye on during the 2018 season.

Andrew Luck, QB, Colts

The Colts appeared to be set at quarterback for the next decade after 2012 first-overall pick Andrew Luck led Indianapolis to three-straight playoff appearances in his first three NFL seasons. Luck and the Colts hit rock bottom in 2017. Complications from offseason shoulder surgery kept Luck from playing last season. A conservative approach has since been taken with Luck's throwing shoulder, which was initially injured in 2015. He is expected to be under center when the season opens in September. Another setback or an inability for Luck to regain the form he showed at the beginning of his career could force the Colts to start hedging their bets at quarterback.

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J.J. Watt, DE, Texans

It wasn't too long ago when Watt was considered the closest thing to a modern-day Reggie White, who is arguably the greatest defensive football player of all-time. Heading into the 2016 season, Watt had just won consecutive NFL Defensive Player of the Year awards and posted a league-leading 17.5 sacks in 2015. Watt played only the first three games in 2016 because he suffered a setback in returning too quickly from back surgery for a herniated disc, which he had right before the start of training camp. A second surgery was necessary. Watt was limited last season to five games because of a broken leg and did not have a sack. If Watt is a shadow of his former self or can't shake the injury bug, it wouldn't be a surprise for the Texans to release the reigning Walter Payton NFL Man of the Year or ask him to take a pay cut. Watt will have three years remaining on his contract for $46 million after this season.

Jameis Winston, QB, Buccaneers

Winston is expected to receive a three-game suspension for violating the NFL's personal conduct policy. The discipline, which has yet to be formally announced, relates to his alleged groping of a female Uber driver in March 2016. The alleged incident is a reminder of Winston's off-the-field behavior while at Florida State, which included a sexual-assault accusation. On the field, the 2015 first-overall pick hasn't quite progressed as expected, although he is the only quarterback in league history to throw for at least 4,000 yards in each of his first two seasons. Winston needs to cut down on his turnovers. Only Jaguars quarterback Blake Bortles has thrown more interceptions than Winston (44) since his entry into the NFL. Winston's 15 lost fumbles during that span are a league high. The Buccaneers have picked up their fifth-year option on Winston in 2019 for $20.922 million. The option was guaranteed for injury upon exercise and becomes fully guaranteed on the first day of the league year in the fifth contract year (March 13, 2019). It remains to be seen whether the allegations will impact Tampa Bay's decision on the fifth year if Winston doesn't raise his level of play this season. Another misstep almost certainly will.

Joe Flacco, QB, Ravens

The Ravens put Flacco on notice by taking 2016 Heisman Trophy winner Lamar Jackson with the last pick in the first round of this year's NFL draft. Flacco has been a slightly above average quarterback at best in the five seasons since being named Super Bowl XLVII MVP. His stellar play during the 2012 playoffs led to him briefly becoming the NFL's highest-paid player in 2013. The Ravens have been to the playoffs only once since their Super Bowl XLVII win. Nobody has come close to the slightly over $112 million Flacco has made during this span. Giants quarterback Eli Manning is second in the NFL with $97.65 million. The first year the Ravens can move on from Flacco's contract without adverse salary cap consequences is 2019, although he has the NFL's sixth-highest cap number at $26.5 million. Flacco should probably treat the 2018 season as a league-wide audition for his next NFL destination since Jackson is Baltimore's quarterback of the future. The Ravens would have a $16 million cap charge in 2019, a $10.5 million cap savings, by releasing or trading Flacco next offseason.

Richard Sherman, CB, 49ers

Sherman, who is recovering from tearing his right Achilles during the middle of the 2017 season, quickly landed with the 49ers after the Seahawks released him in early March. Operating without an agent, Sherman negotiated a team friendly three-year, $27.15 million contract for himself, which is worth a maximum of $39.15 million through not-so-easily-achievable salary escalators and incentives. The 30 year old is attempting to follow in Buccaneers cornerback Brent Grimes' footsteps. Grimes earned a Pro Bowl berth in 2013 after tearing his Achilles in the 2012 season opener with the Falcons, when he was 29. Should Sherman overcome his injury like Grimes did, he may regret that he didn't bet on himself with a one-year "prove it" deal.

Muhammad Wilkerson, DE, Packers

Wilkerson didn't come close to living up to the five-year, $86 million deal he signed in 2016 as a franchise player before the Jets released him in March. He made $36.75 million over the last two years. Wilkerson signed a one-year, $5 million contract (worth up to $8 million through incentives) with Green Bay to try to resurrect his career. He was coming off a career-high 12 sacks in 2015 when he signed his big deal.

Ryan Tannehill, QB, Dolphins

Before he re-injured his left knee last preseason, 2017 was going to be a crucial year for Tannehill's future in Miami because he hasn't consistently lived up to being the eighth-overall pick in the 2012 draft. Tannehill originally hurt his knee late in the 2016 season. He missed 2017 after surgery to repair the ACL in his knee. Fortunately for Tannehill, Miami didn't bring in any serious competition at quarterback through free agency or the draft. Unless Tannehill can thrive under head coach Adam Gase this season, it might become time for the Dolphins to start looking for a quarterback who can. Tannehill has the NFL's fifth-largest 2019 salary-cap number at $26,611,666. The Dolphins would pick up $13,188,332 of cap space by parting ways with Tannehill next year.

Tyler Eifert, TE, Bengals

A back injury requiring surgery limited Eifert to two games in 2017, which has been a recurring theme with him. Eifert has played only 39 games during his five NFL seasons because of various injuries (ankle, back, elbow, etc). When healthy, Eifert is one the NFL's best red-zone threats. He led NFL tight ends in 2015 with 13 touchdown receptions while earning a Pro-Bowl berth. The injuries made Eifert an ideal candidate for a one year prove-it deal, which he signed to remain in Cincinnati. Eifert's 2013 NFL draft contemporaries (Zach Ertz, Travis Kelce and Jordan Reed) are on long-term extensions averaging between $8.5 million and $9.35 million per year. Erasing concerns about durability may be Eifert's only path to similar compensation.

Jason Verrett, CB, Chargers

Persistent problems with a partial ACL tear in his left knee suffered in 2016 have limited Verrett to four games over the last two seasons. The 2014 first-round pick has missed 39 of 64 regular games in his four-year NFL career. He earned Pro-Bowl honors in 2015, his only healthy season. Verrett can look to Bears cornerback Kyle Fuller, a fellow 2014 first-round pick, as inspiration. The Bears passed on Fuller's fifth-year option worth $8.526 million, which is Verrett's salary this year, after he missed the 2016 season because of preseason knee surgery. A bounce-back 2017 season led to Chicago putting a seldom-used transition tag on Fuller this offseason. The Bears matched the four-year, $56 million offer sheet Fuller signed with the Packers.

Robert Quinn, DE, Dolphins

Quinn landed a four-year extension for slightly over $57 million in 2014 after 19 sacks during a breakout 2013 campaign. He has only 17.5 sacks over the last three seasons. Quinn has missed a season worth of games during this span because of multiple injuries (back, shoulder, etc.). He wasn't a good fit at outside linebacker in Rams defensive coordinator Wade Phillips' switch to his trademark 3-4 defense prior to last season. Quinn is getting a new lease on his football life after the Rams traded him to Miami in March. He gets to return to defensive end, where he has been most comfortable and effective.

Kevin White, WR, Bears

The Bears declined to pick up the $13.924 million fifth-year option in 2019 for 2015's seventh-overall pick. It was for good reason. White was too much of an injury risk for the Bears to exercise the option. He has caught 21 passes for 193 yards in the five games he has played during his three years with the Bears. A stress fracture in White's shin kept him out of action in his rookie season. A broken ankle limited White to four games in 2016. White spent the 2017 season on injured reserve after breaking his collarbone in the first game. New Bears head coach Matt Nagy is cautiously optimistic about White after a strong offseason. White could have a difficult time turning his good showing into production even if he can stay healthy due to the additions of Allen Robinson and Taylor Gabriel in free agency and Anthony Miller in the second round of the draft.

Ereck Flowers, OT, Giants

Making Nate Solder the NFL's highest-paid offensive lineman to take over at left tackle, which is where Flowers has played the last three seasons, is an indictment of his performance. Consequently the Giants didn't pick up Flowers' 2019 fifth-year option for $12.525 million. Flowers expressed his displeasure with Solder's signing by skipping the early part of the offseason workout program. The Giants are giving Flowers a chance to compete for the starting right tackle job.