10 Key Injuries to Monitor Entering NFL Training Camps

Training camps are opening up throughout the country, giving us a chance to get first full glimpses at new acquisitions, highly touted rookies and—of course—those who are either returning from or trying to return from injuries. 

Dozens of key NFL players are dealing with injuries headed into camp, and the sad reality is that dozens more will encounter them in the weeks to come. But right now, the majority of the NFL world's eyes are on these 10 injured stars or stars-to-be. 

Houston Texans DE J.J. Watt: Herniated Disc

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Three-time Defensive Player of the Year J.J. Watt underwent surgery last week to repair a herniated disc, which puts his availability in jeopardy for the start of the regular season.

An initial report from NFL Media's Ian Rapoport indicated Watt's recovery time would be in the range of six to eight weeks, but NFL Media's Mike Garafolo tweeted less than an hour later that Watt could miss up to 10 weeks. 

Watt's Houston Texans open the season in less than seven weeks, so it's entirely possible the 27-year-old will miss the first game(s) of his career. That's particularly scary because we'd be entering the unknown. While Houston still made the playoffs despite the fact Watt was playing hurt last season, we have no evidence that the Texans can survive without their best player.

The whole thing might end up putting a lot of pressure on the offense, which is far from ideal with $18 million quarterback Brock Osweiler already facing pressure as an opening day starter for the first time in his career. 

New York Giants WR Victor Cruz: Torn Patellar Tendon, Injured Calf

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Victor Cruz was a 1,500-yard receiver in 2011 and a Pro Bowler in 2012. He fell two yards short of 1,000 again in 2013 despite missing two games. But he's been able to play in just six games since the end of that 2013 campaign, and he continues to face an uphill battle entering his age-30 season. 

Cruz tore his patellar tendon midway through the 2014 season, missed the rest of the year and then injured his calf while trying to come back in the summer of 2015. He said the calf injury—per Jordan Raanan of NJ.com—came about as a result of overcompensation. It caused him to undergo surgery and cost him his entire 2015 campaign. 

A torn patellar tendon is one of the toughest injuries in sports to recover from. Throw in a second soft-tissue injury, and it's fair to wonder if Cruz's body has begun to fail him. 

It helps that the New York Giants already have a superstar wide receiver in Odell Beckham Jr., and they smartly used a second-round pick on potential starting wideout Sterling Shepard. But quarterback Eli Manning and the rest of the offense would benefit greatly from having an experienced safety valve like Cruz in the slot. 

Per the New York Daily News, Cruz says he'll be "ready to go" when the Giants start training camp. But that was also the case last summer, so don't start counting unhatched chickens. 

Buffalo Bills WR Sammy Watkins: Foot Surgery

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Coming off a 1,000-yard campaign with a new coaching staff and a new quarterback, it was natural to expect Buffalo Bills wide receiver Sammy Watkins to explode in his third NFL season. But the 2014 No. 4 overall pick has been sidetracked by a broken foot, which required surgery in the spring. 

The good news is Watkins appears to be close to 100 percent as camp arrives. 

"As far as sprinting and stuff, I'm moving and doing that 100 percent," Watkins said this week, according to Chris Brown of the team's official website. "Gassers, 100s, everything in the workout room. Any explosiveness, I'm doing that. I'm doing the cuts, but certain things are full speed and certain things aren't."

It's still not clear how active he'll be at the outset, but that summary alone is encouraging. Especially considering that in early June, Watkins wasn't sure he'd be able to practice at all in camp, per Tyler Dunne of the Buffalo News. 

Now it's beginning to look as though he'll be back on track well before the start of the regular season, much to the delight of Bills fans, Watkins fantasy owners and Tyrod Taylor. 

New York Jets DE Muhammad Wilkerson: Broken Leg

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It's easy to forget that New York Jets defensive lineman Muhammad Wilkerson is still recovering from a broken leg, because all of the talk regarding Wilkerson this offseason has pertained to his contract. 

But now that trade rumors have been squashed, the franchise tag has been thrown away and the 26-year-old Pro Bowler has himself a shiny new contract, the focus has started to turn to Wilkerson's injury. The Jets open training camp this week, but according to ESPN.com's Rich Cimini, their top sack man from 2015 isn't likely to be ready to practice. 

Still, the regular season is still more than six weeks out. Wilkerson believes he'll be back in time for the Jets' Sept. 11 opener against the Cincinnati Bengals. 

"I will be ready for Week 1," he said last week, per the New York Times, adding that "rehab is going well."

"I'm running four times a week and just taking it day by day. I'm focusing on my leg and rehabbing each and every day. When the coaches feel it is time for me to get out there on the field and I am ready to go, I will be out there."

Jets fans had better hope so, because nobody else on that team had more than five sacks last season. Wilkerson had 12. 

Baltimore Ravens WR Steve Smith: Ruptured Achilles Tendon

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We've learned not to doubt veteran Baltimore Ravens wide receiver Steve Smith, who has spent a decade-and-a-half defying odds at the NFL level. Now, an inspired Smith is once again attempting to baffle the football gods by pushing his retirement back a year for a shot at a title and 1,000 career receptions. 

But Smith isn't just battling football gods and Father Time. He's also battling an acute injury. See, his 2015 swan song season was destroyed when he tore his Achilles tendon Week 8 against the San Diego Chargers. He's been fighting ever since to get back in time for Baltimore's Week 1 matchup with the Buffalo Bills. 

Smith hasn't participated in offseason workouts, won't take part in the preseason and—per ESPN.com's Jamison Hensley—will be limited to route-running in training camp. He's already on the active/PUP (physically unable to perform) list, so his status for Week 1 has to be considered up in the air. 

That's far from ideal for a Ravens team that is also waiting on second-year receiver Breshad Perriman. This leads us to our next slide. 

Baltimore Ravens WR Breshad Perriman: Partially Torn ACL

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Baltimore (and Owings Mills, Maryland, where the Ravens hold training camp) will be the capital of the football-injury world this August. Veteran Ravens Steve Smith, Joe Flacco and Terrell Suggs are all trying to get back to 100 percent after suffering major injuries last season. 

We'll be watching all of those guys closely, but I think Ravens fans might be particularly concerned with the status of a player who has never taken an NFL snap. That's because with Smith being a question mark, this was supposed to be a big first season for 2015 first-round draft pick Breshad Perriman. But Perriman, who missed his entire rookie season due to a PCL sprain in his right knee, partially tore his left ACL last month. 

Key word there is "partially," because there's actually plenty of hope that the 22-year-old former Central Florida wide receiver could be in the lineup at the start of the regular season. He'll start camp on the active/PUP list, but the expectation—per NFL Media's Ian Rapoport and NFL.com's Jeremy Bergman—is he'll be able to return at some point in August before making his NFL debut against Buffalo on Sept. 11. 

That would be huge, especially because there's a lot of uncertainty regarding Smith. 

Pittsburgh Steelers RB Le'Veon Bell: Torn MCL and PCL, Potential Suspension

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Three potential reasons why Pittsburgh Steelers running back Le'Veon Bell might not be active Week 1 against the Washington Redskins: 

1. His right MCL. 

2. His right PCL. Both were torn about eight months ago. 

3. The four-game suspension that ESPN.com's Dan Graziano reports he's facing for missing a drug test.

First, that knee injury, which ESPN.com's Jeremy Fowler called the "Steelers' big offseason mystery" in the spring. He did resume running in March, but not a lot of light was shed on his rehab from surgery. He's yet to practice fully with the team. 

"LeVeon Bell is trying to come back from tears to his PCL and MCL, which is actually harder to recover from than an ACL tear," wrote Dr. David Chao for the Real Football Network. "Think of a barstool. If two legs are a little wobbly, that stool is much less stable than if one leg is unsteady. I know people are excited about his return in Pittsburgh, but I'd be surprised if he doesn't start the season on PUP."

As for the suspension, it might be easier to swallow if indeed Bell isn't ready in September. That said, he appears to be ready to fight. 

"I'm gonna win the appeal...ppl have no idea what happened, but don't worry...let em hate," Bell wrote in a comment to a fan on Instagram this week, per Ryan Wilson of CBSSports.com. "When I end up missin no games at all, ppl for sure gonna try to love me again and I'm only ridin with my LOYAL fans!!"

Well then. Maybe there is hope for the All-Pro back, but don't expect clarity before camp opens this week. 

Kansas City Chiefs OLB Justin Houston: ACL Surgery

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Kansas City Chiefs pass-rushing stud Justin Houston was shut down early in 2015 due to a knee injury, which wasn't considered to be extremely serious. In fact, he even returned briefly in the playoffs. But something wasn't right with the ACL in that left knee, and he underwent a procedure in February that was initially expected to keep him out six to 12 months. 

Now, that's a broad projection. In the best-case scenario, that could mean Houston would be back in time for the second half of training camp. Worst-case, he's gone for the entire 2016 season. All we know right now is the Chiefs will be opening camp without him, but that the team sounds optimistic he'll play in 2016.

That would be nice, since the handsomely paid Houston has led the Chiefs in sacks in each of the last four seasons and had a 22-sack campaign in 2014. The team may have gone 5-0 without him late last season, but Kansas City needs its best rusher in order to compete for a championship in 2016. 

In the next few weeks, we should at least get a feel for the likelihood of that happening. 

Arizona Cardinals DB Tyrann Mathieu: Torn ACL

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Versatile Arizona Cardinals defensive back Tyrann Mathieu played 14 games last year before suffering a torn ACL, but that was still enough to earn an All-Pro nod. Now, seven months later, one of the most talented young players in the game is fighting to get back in time for his team's season-opening matchup with the New England Patriots. 

The 24-year-old is expected to start camp on the physically unable to perform list, per Darren Urban of AZCentral.com. But from that point forward, his progress will be monitored with much intensity.  

And for good reason. Pro Football Focus graded 206 defensive backs who played at least 25 percent of their teams' snaps in 2015. Only one of those 206 players finished with a grade above 18.0. That was Mathieu, whose grade of 28.1 was 57 percent higher than every other cornerback or safety in the league. He's an incredibly unique, ball-hawking hybrid safety-corner who is yet to reach his prime, and Arizona is going to need him in order to make a Super Bowl run. 

San Francisco 49ers QB Colin Kaepernick: Shoulder, Thumb and Knee Surgeries

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The San Francisco 49ers may or may not be looking for an excuse to hand their starting quarterback job to Blaine Gabbert, but Colin Kaepernick seems to be making the decision easy.

The talented but inconsistent and flawed young quarterback underwent surgery on his shoulder, knee and thumb after landing on injured reserve late last season. That, put simply, is a lot of surgery, and it has left Kaep behind in that quarterback battle throughout the offseason.

The 28-year-old did throw at OTAs, and he told the media last month that he expected to be "full go" for training camp. Matt Barrows of the Sacramento Bee reported that Kaepernick has been medically cleared to practice in full.

Still, he's fighting an uphill battle, and we're yet to see how he'll rebound from last season's injuries and the multiple surgeries that followed.