Some of the best players the NFL has to offer won’t be playing when their teams take the field to open up the season. Injuries have hit some teams harder than others, but they are a constant factor for every franchise in the league. For the purposes of this list, we’re focusing on the most devastating NFL injuries that occurred this summer.

Some names are nationally recognizable, for good reason. Others are not, but their inability to contribute to their teams’ efforts will be keenly felt. Among them is a rising star quarterback, a handful of top receivers, plenty of top defenders and offensive linemen.

These players were all expected to be huge contributors to their respective teams. Now they’re either out for the season or working through difficult injuries with the hope of making a return at some point later in the campaign.

Anthony Hitchens, linebacker, Dallas Cowboys

The Cowboys will be without their starting inside linebacker for at least eight weeks after he suffered a knee fracture in the third preseason game. He’s started 36 games the past three years and all 16 last season. It’s really a tough blow to a defense that features a front seven that was already in trouble after pass rusher David Irving was suspended four games due to PEDs. Jaylon Smith is the obvious replacement here in the starting lineup. However, the Cowboys have been slowly working him back after he missed his entire rookie campaign due to a catastrophic knee injury suffered in his final college game. Even if he’s ready, the simple truth is that Dallas’ linebacking corps is frightfully thin.

Forrest Lamp, offensive guard, Los Angeles Chargers

Without a question, Lamp was one of the best offensive linemen at any position to enter the 2017 NFL Draft. The Chargers were thrilled to nab him near the top of the second round, and he was quickly inserted into the starting lineup at left guard. A team that has long struggled to feature a strong offensive line, Los Angeles was counting on him to not only be a big player this year, but for many years to come. So it was a harsh blow for the team and the player himself when Lamp was lost for the season with an ACL injury.

Trent Murphy, outside linebacker, Washington Redskins

The Redskins were already going to be without Murphy the first four games of the season after he was suspended for PEDs. But losing a guy for the first quarter is nothing compared to the entire campaign, which is what happened when Murphy suffered an injury to his knee, tearing both his ACL and MCL. This is a fourth-year player who came on strong last year with 9.5 sacks, so he’ll clearly be missed. This is especially true when you consider the Redskins aren’t loaded with talent on the edge.

George Fant, left tackle, Seattle Seahawks

Seattle Seahawks left tackle George Fant was lost for the season with a torn ACL in preseason Week 2

The Seahawks feature championship-caliber talent at many positions. But the offensive line is universally recognized as the biggest area of weakness. Russell Wilson has endured 123 sacks the past three seasons and was a shell of himself as a dual-threat passer last year after enduring multiple injuries. With all that in mind, losing Fant, the starting left tackle, for the season is going to leave a lasting mark on this team’s ability to compete offensively all year long.

Tank Carder, inside linebacker, Cleveland Browns

Cleveland is building a very impressive defense, and the players have all responded positively to Gregg Williams guidance this preseason. However, one of the real areas of weakness was at inside linebacker. This was clearly seen when Carder was given an opportunity to start this year, despite only starting in two previous games his entire five-year career. Then, Carder was lost for the year when he tore his ACL in the team’s second preseason game. This injury put second-year linebacker Joe Schobert in the spotlight and puts tremendous stress on the team’s depth at the position.

Quincy Enunwa, wide receiver, New York Jets

Talk about a gut punch. The Jets were counting on Enunwa to be the top dog in an inexperienced receiving corps. He was clearly the best remaining receiver on the roster after general manager Mike Maccagnan’s offseason purge. He had caught 58 passes for 857 yards and four touchdowns in 2016 and figured to get a ton of targets as the No. 1 receiver this year. Then, Enunwa suffered a neck injury that will keep him out the entire season. It’s a brutal turn of events for Enunwa on a personal level and puts a ton of pressure on the team to develop young talent on an offense devoid of quarterback talent.

Derek Rivers, defensive end, New England Patriots

The Patriots landed what many considered to be the steal of the 2017 NFL Draft when they selected Rivers No. 83 overall out of Youngstown State. A talented pass rusher, he was almost universally coveted by scouts as a small-school gem. The Patriots had big plans for the rookie and needed him to come through. As loaded as this team is across the board, the one area of weakness is that New England doesn’t feature many guys that can get to the quarterback off the edge. That’s why the Pats traded for Kony Ealy. Though, that didn’t work out either, which accentuates the loss of Rivers all the more. He won’t play a single down this year after suffering a knee injury in mid August.

Nico Siragusa/Alex Lewis, offensive guards, Baltimore Ravens

There are a couple of teams that feel especially cursed as it pertains to injuries in recent years. Baltimore certainly qualifies as one of them. Two offensive guards who could have been starters, or at the least rotational guys, were lost for the season early on during training camp. Siragusa, a rookie out of San Diego State, suffered a catastrophic knee injury and will need considerable time to recover. Then Lewis, who was seen as a potential starter at left guard, suffered a torn labrum.

Combined with the sudden retirement of John Urschel, and having already lost right tackle Rick Wagner in free agency, these are injuries that could doom Baltimore’s offense before it ever hits the field. Oh, and Joe Flacco has a back injury that has sidelined him throughout camp. It’s not looking good, Ravens fans.

Raekwon McMillan, inside linebacker, Miami Dolphins

The Dolphins were thrilled to draft McMillan, who was already well on his way to earning the starting nod at inside linebacker this summer. The rookie out of Ohio State quickly showed himself to be capable of shouldering the load that comes with being the quarterback of the defense. Then disaster struck, as McMillan suffered a season-ending knee injury in the second week of August. The injury prompted the Dolphins to pick up veteran Rey Maualuga, who had been released by the Cincinnati Bengals earlier this year and showed up to Miami out of shape.

Cameron Meredith, wide receiver, Chicago Bears

Chicago Bears receiver Cameron Meredith

Anyone who saw this injury in the third preseason game knew immediately that Meredith would not play another down in 2017. It was brutal.

Meredith suffered at least an ACL tear, if not much more. He’s a kid that came on strong last year out of the blue as a second-year player out of Illinois State, catching 66 passes for 888 yards and four touchdowns. After that eye-opening campaign, he was expected to be a big part of what the Bears were doing this year. The season-ending injury he suffered will negatively impact Chicago’s offense this year, at least.

Dominique Easley, defensive tackle, Los Angeles Rams

Easley, a former first-round pick by the New England Patriots in 2014, was slated to be a key cog in Wade Phillips’ 3-4 defense this season in Los Angeles. At the very least, he was going to be a heavily utilized rotational player, and at best he was on his way to earning a starting role. That all came screeching to a halt, however, when Easley tore up his knee early during training camp. Combined with the continued holdout of star lineman Aaron Donald, the Rams have some serious depth issues now up front on the defensive side of the ball.

Ryan Tannehill, quarterback, Miami Dolphins

Now, Jay Cutler is a heck of a backup plan. And he might in the end work out nicely for Miami. But let’s not kid ourselves about just how devastating Tannehill’s injury was for Miami. Both in the short and long term, his knee injury really complicates things for the Dolphins. If Cutler reverts to his chuck-it-and-pray ways, then there’s no way the Fins are making it back to the playoffs. And he’s just a one-year (maybe two on the outside) fix even if he plays well.

Tannehill has been a guy who’s been just on the outside of franchise-quarterback material for a few years. The team has an out in his contract after this year. It’s not a guarantee he’s going to be the guy going forward, so there’s a lot up in the air right now.

Kerry Hyder, defensive end, Detroit Lions

A relatively unknown player until last year, Hyder burst onto the scene as the best pass rusher on Detroit’s defense. In fact, he was such an unknown figure that he wasn’t even included on Pro Bowl ballots last fall. Hyder finished the season with more sacks than any other Lions player (eight) and was coming on strong this summer. Unfortunately, he ended up tearing his Achilles tendon and is out the entire season. This is a massive blow for Detroit’s defense, which already was very thin in terms of pass rushers. Ziggy Ansah cannot get healthy fast enough, and even if he does return to form he might not be enough.

Terron Armstead, left tackle, New Orleans Saints

Armstead is another player who is going to return to the field at some point this season, barring a setback in his recovery. He suffered a torn labrum even before training camp began and was scheduled to miss anywhere between four and six months following surgery. The Saints will miss him dearly until he’s ready to come back, however. Armstead is one of the NFL’s best pass-blocking left tackles, and Drew Brees has counted on him for protection. Rookie Ryan Ramczyk is going to receive a baptism by fire immediately this year as Armstead’s short-term replacement.

Denzel Perryman, inside linebacker, Los Angeles Chargers

Perryman will be sorely missed for as long as he remains sidelined with an ankle injury that required surgery. He suffered the injury during the team’s first preseason game and is slated to be out anywhere between eight and 10 weeks as he recovers. In the meantime, the Chargers are relying on either Korey Toomer or Nick Dzubnar to fill the void. The drop-off from Perryman to this duo is significant, and it’s not yet decided which one of them will take on the starting duties heading into the final preseason game.

Julian Edelman, wide receiver, New England Patriots

Patriots receiver Julian Edelman suffered a devastating knee injury.

How much will Tom Brady miss Edelman? Well, in the past four seasons, this guy has caught at least six passes averaging at least 66 yards per game for the Patriots. That’s elite production right there, and it’s not easily replicated. Suddenly, it looks like the Brandin Cooks trade was prophetic. Though, Cooks’ game differs quite a bit from what Edelman has done, meaning the Patriots might need to get seriously creative to make up for the production lost due to his season-ending ACL injury.

Ryan Kelly, center, Indianapolis Colts

The Colts already featured a sketchy offensive line even with Kelly as a reliable centerpiece. Now that he’s out for likely half the season due to a foot injury, this unit is Swiss Cheese. Of further concern is the fact that left guard Jack Mewhort has been dealing with an undisclosed issue and hasn’t been practicing of late. Indianapolis’ offense is a wreck right now, and we haven’t even yet discussed Andrew Luck, who we’ll get to in a bit.

Spencer Ware, running back, Kansas City Chiefs

The Chiefs released Jamaal Charles this offseason in part because they were confident that Ware could shoulder the load instead. Suddenly, Charles is coming on strong for the Denver Broncos while Ware is likely headed for season-ending knee surgery. That’s the vicious nature of the NFL. Now it’s up to rookie Kareem Hunt to be the workhorse running back in Andy Reid’s offense, which also watched top receiver Jeremy Maclin depart this offseason.

Tavon Young, defensive back, Baltimore Ravens

The Ravens had some high hopes for Young this season after he emerged as the go-to slot defender last season as a fourth-round rookie out of Temple. He earned high grades from the folks at Pro Football Focus, and the general sentiment around the league is that this kid was going places. Then he suffered an ACL injury in early July, which is hard luck for him personally and definitely a loss for Baltimore’s defense as a whole. The Ravens have been snake bitten the past couple of years and appear to be destined to miss the playoffs for the third straight year.

Andrew Luck, quarterback, Indianapolis Colts

Andrew Luck

Luck’s story is fascinating, and it’s trending towards disturbing. He suffered a shoulder injury at the beginning of the 2015 season. Then he proceeded to play through it for two years while sustaining other injuries due to Indianapolis’ staunch determination to not protect its top investment. Finally, in January of this year Luck had his shoulder surgically repaired. To this point, he has yet to practice with his teammates, and head coach Chuck Pagano said on Monday he still has yet to see his quarterback throw a single pass.

The season is less than two weeks away, folks. Luck isn’t going to start in Week 1. At this rate, he might not start for another month, or longer. The Colts are already on the verge of throwing the season away as it is. If he’s out for any extended period of time, they might as well keep him out all year to ensure he doesn’t get injured again playing behind a wrecked offensive line.