It is a well-accepted axiom in the NFL preseason that the key is not performance, it's health.
Don't lose a major contributor.
Several teams failed in their mission this summer, although a few of them should be able to survive the loss (or losses). Others must be wondering if it pays to have regulars see the field at all before September.
Here's a team-by-team look at significant injuries or, in a few cases, who avoided being damaged.
NEW ENGLAND - As loaded as they appear to be, losing WR Julian Edelman (knee) for the season was a blow for the Patriots. Edelman has been Tom Brady's favorite target and while there are plenty of others for Brady to connect with, the absence of Edelman has to have an effect.
MIAMI - When quarterback Ryan Tannehill took a misstep on a run and injured his knee, coach Adam Gase turned to Jay Cutler, with whom he has a successful history. Cutler came out of the broadcast booth to join the Dolphins, who have had a tough summer. Rookie Raekwon McMillan (right ACL), projected to start at middle linebacker, is also out for the season; starting G Ted Larsen is expected to miss much of it with a torn right biceps, and No. 3 cornerback Tony Lippett tore his Achilles tendon during practice.
BUFFALO - Both starting QB Tyrod Taylor and veteran reserve T.J. Yates wound up in the NFL's concussion protocol. Starting LT Cordy Glenn did not play a preseason game because of nagging soreness in his left foot.
NEW YORK JETS - The major injury was WR Quincy Enunwa, who sustained a bulging disk in his neck after falling during a play in a team's scrimmage. He'll miss the entire season after he was expected to be the No. 1 receiver in what was already an inexperienced group.
PITTSBURGH - It's been a successful summer for Pittsburgh; the Steelers have no long-term injuries to any starters. S Mike Mitchell has been dealing with a lower-body injury and hasn't practiced since July 30.
BALTIMORE - One team that wishes preseason didn't exist. TEs Dennis Pitta and Crockett Gillmore, CB Tavon Young, OLs Nico Siragusa and Alex Lewis, LB Albert McClellan, RB Kenneth Dixon and WR Tim White all were hurt, and QB Joe Flacco (back) was hobbled for a lengthy portion of August. McClellan (torn ACL) is out for the season. He played in all 16 games last season, starting 11, and finished with 52 tackles.
CINCINNATI - Not a bad summer injury-wise; suspension are another matter. But top special teams player Cedric Peerman suffered a shoulder injury and went on injured reserve.
CLEVELAND - Starting left guard Joel Bitonio sustained an unspecified knee injury during camp. Bitonio missed 11 games last season after undergoing surgery on a torn foot ligament, yet the team signed him to a five-year, $51 million deal during the offseason.
HOUSTON - Obviously, with the damage in Houston from Hurricane Harvey, the Texans have far greater concerns. They did lose WR Will Fuller, who broke his collarbone early in camp.
TENNESSEE - Another team hurt at wide receiver. Top selection Corey Davis missed all but the opening week of training camp with an injured hamstring. The Titans have targeted the season opener against Oakland for his return.
INDIANAPOLIS - No Luck, as in Andrew Luck. The star quarterback hasn't practiced after having offseason surgery on his throwing shoulder. Add in starting center Ryan Kelly (foot) going down and needing surgery, and top cornerback Vontae Davis injuring his groin in Week 3 of the preseason and it doesn't look good in Indy.
JACKSONVILLE - The Jaguars' only major injury was to long snapper Carson Tinker, who tore a knee ligament during a non-contact drill in training camp and had season-ending surgery.
KANSAS CITY - A big one: The Chiefs lost starting RB Spencer Ware (right knee ligaments) for the season. But they do have depth there, particularly with the sharp work of rookie Kareem Hunt so far.
OAKLAND - A relatively seamless summer, with the most notable injuries to reserve offensive lineman Denver Kirkland (leg) and backup safety Keith McGill (foot). Uncertainty surrounded first-round pick Gareon Conley since minicamp in June when he hurt his shin, but he's expected back for the opener.
DENVER - A bunch of nagging ones, but the main longer-term problem was backup QB Paxton Lynch hurting his right shoulder. Strong safety T.J. Ward pulled his right hamstring early in camp and missed the entire preseason, endangering his roster spot.
LOS ANGELES CHARGERS - First-round pick WR Mike Williams' season is in jeopardy after hurting his back in rookie camp. Rookie G Forrest Lamp tore a right knee ligament and is out for the season. He seemed likely to win a starting job.
DALLAS - Anthony Hitchens, who started all 16 games at middle linebacker last year but can play all three positions, broke a bone in his right knee against Oakland.
NEW YORK GIANTS - Scary but maybe not too serious, star WR Odell Beckham Jr. went up for a high pass against Cleveland and was hit directly on his knee. Turned out to be no structural damage. But Giants lost DT Jay Bromley (left knee), who was having great camp.
WASHINGTON - The Redskins were betting on a career revitalization from Cleveland's 2011 first-round pick Phil Taylor after two years out of the NFL because of knee injuries. The DT tore his left quadriceps tendon and is out for the season.
PHILADELPHIA - Relatively unharmed, the Eagles' backup QB Nick Foles hasn't played in any preseason games because of an elbow injury.
GREEN BAY - One of the luckier squads, with only rookies LB Vince Biegel and DT Montravious Adams being hobbled.
DETROIT -LT Taylor Decker is out indefinitely, recovering from surgery on his right shoulder. Decker will be replaced by Greg Robinson, a flop with the Los Angeles Rams, who used the No. 2 overall pick from the 2014 NFL draft.
MINNESOTA - With the Vikings, it's more who has been missing long term. QB Teddy Bridgewater is still on the PUP list after a dislocation and multiple ligament tears in his left knee suffered in practice on Aug. 30, 2016. DT Sharrif Floyd remains out indefinitely with nerve damage in his right knee, an injury stemming from arthroscopic surgery he had last season.
CHICAGO - A weak team to start with, Chicago has a big hole at receiver with Camn Meredith suffering a season-ending knee injury. He could have been the Bears' top wideout.
ATLANTA - Standout RB Devonta Freeman spent two weeks in concussion protocol and missed the last three preseason games. Freeman is expected to be ready to play in the regular season opener at Chicago, but WR Devin Fuller will miss the season with a knee injury. It is the second straight year he has had a season-ending injury before playing a game.
TAMPA BAY - The Bucs escaped relatively unscathed, with perhaps the most notable issue a right shin laceration suffered in practice that sidelined CB Brent Grimes for the preseason.
NEW ORLEANS - The Saints will start the season without LT Terron Armstead (offseason shoulder surgery) and starting CB Delvin Breaux (surgery in mid-August to repair stress fracture in his left leg). DT Nick Fairley was ruled out for the season with a heart condition during the summer.
CAROLINA - Most significant injury was to DT Vernon Butler, the team's first-round pick in 2016, who may miss a week or two with a sprained left knee. But there is also a chance he can make it back and play Week 1. Too early to know.
SEATTLE - As if the Seahawks didn't struggle enough on the O-line, their weakest position, starting LT George Fant tore an ACL and damaged his MCL in the second preseason and is out for the season.
ARIZONA - Does GM Steve Keim's torn ACL count? Special teams took the biggest hit because rookie T.J. Logan was expected to return punts and kicks but is out at least eight weeks, and maybe for the season, with a broken wrist.
LOS ANGELES RAMS - DL Dominique Easley tore a knee ligament for the third time in his career, sidelining him for 2017. He was a projected starter after a solid 2016.
SAN FRANCISCO - The 49ers lost projected starting ILB Malcolm Smith for the season with a torn pectoral muscle. They also lost starting RG Joshua Garnett to a knee injury and he could miss the start of the season.
For more NFL coverage: http://www.pro32.ap.org and http://www.twitter.com/AP-NFL