San Francisco 49ers quarterback Jimmy Garoppolo is back, but the team is still reeling from key injuries. (John Hefti/AP)

The NFL needs to cut down the number of preseason games. If you’re looking for a reason as to why, check out the participation of the first full week of exhibition matchups. Nineteen starting quarterbacks sat out their preseason openers. The ones who did play made quick exits.

Roughly half of the NFL coaches treated the entirety of their preseason openers as they do their preseason finales, not playing any starters. Los Angeles Rams Coach Sean McVay said he doesn’t plan to play his starters at all in the preseason for a second straight year.

It’s clear something has to give. The problem is finding a way to replace the revenue from preseason games, because cutting even one has a costly impact. It seems unlikely the owners will be able to talk the players’ union into swapping preseason games for more regular season games in the next collective bargaining agreement, but most everyone seems to agree the preseason is simply too long, including Commissioner Roger Goodell, who has advocated cutting the preseason to two or three games because of the quality of play. Now is the time to do it.

Here are more takeaways from the start of NFL training camps and the first week of preseason games:

Injuries are a problem for the 49ers again.

The San Francisco 49ers restructured their training and medical staffs after two seasons in which they placed around 45 players on injured reserve. But while it probably isn’t related to the new staff, injuries are still a major concern. Defensive end Nick Bosa (ankle), cornerback Jason Verrett (ankle) and cornerback K’Waun Williams (knee) are question marks before the start of the regular season.

Defensive end Dee Ford has an arthritic knee. Tackle Shon Coleman is probably lost for the season with a fractured fibula. Wide receiver Trent Taylor injured his foot in practice, requiring surgery. And there are three carry-over injuries from last year that make center Weston Richburg (knee), halfback Jerick McKinnon (knee) and tight end Garrett Celek (back) question marks for the opener.

The 49ers’ roster is deeper than it was last year, and if quarterback Jimmy Garoppolo can be effective in recovering from the torn ACL he suffered last year, San Francisco could compete for the division title. But the injury trend can’t continue if the 49ers want to move to the eight- or nine-win level, especially in the competitive NFC West.

The Steelers are having a great start to training camp.

Aside from the tragic death of wide receivers coach Darryl Drake, a beloved figure around the NFL, the Steelers are enjoying a productive and distraction-free start to training camp. The offense remains potent even without running back Le’Veon Bell and wide receiver Antonio Brown (more on him later), with an offensive line that is one of the best in football and enough talent at the skill positions for quarterback Ben Roethlisberger.

On defense, new cornerback Steven Nelson has exceeded expectations in coverage. First-round draft choice Devin Bush struggled picking up the defense at first, but he looked great in the preseason opener and should eventually emerge as a Pro Bowl-caliber defender at linebacker.

The NFC North competition is going to be intense.

The Minnesota Vikings’ trade for Baltimore Ravens kicker Kaare Vedvik embodies just how intense the competition is in the NFC North. The Vikings were willing to give up a fifth-round draft pick next year to fix their kicking game, while at the same time preventing the Chicago Bears from fixing their placekicking problems with Vedvik.

Speaking of Chicago, quarterback Mitch Trubisky seems to have improved since the end of last season, when he often struggled after going through the first 15 scripted plays. He looks more comfortable running the offense, one that looks pretty loaded at wide receiver and in the backfield.

The Green Bay Packers, meanwhile, spent $117 million on contracts for pass rushers Za’Darius Smith and Preston Smith, along with using first-round picks on defensive lineman Rashan Gary and safety Darnell Savage Jr. The Packers are young and have more speed on defense. It should be a great three-team divisional race involving the Vikings, Bears and Packers.

Nick Foles should provide Jaguars with a big upgrade on offense.

Those who have ventured through Jacksonville Jaguars training camp this summer have come away raving about how quarterback Nick Foles looks in the offense. His accuracy and leadership have worked well with a decent group of wide receivers. The offense should be much better this year. Plus, running back Leonard Fournette appears to be much more serious about his job and has been having a great camp.

The Seahawks’ offense looks great.

The Seattle Seahawks went to two Super Bowls with a running offense and a great defense. But until Pete Carroll’s young defense comes together, the Seahawks are an offensive team for the time being — and they could be a real good one.

Last year, the Seahawks averaged 30 points per game in the second half of the season. Russell Wilson is having his best offseason and training camp. They have a great one-two punch in the backfield with Chris Carson and Rashaad Penny. Tyler Lockett is among the top 20 wide receivers and has promising young players DK Metcalf, Gary Jennings and David Moore behind him.

If the Seahawks can give up fewer than the 21.7 points per game they did last year, they could challenge the Rams for the NFC West title.

Lamar Jackson looks better, but injury risk remains.

The Baltimore Ravens’ new-look offense is looking better than expected: Second-year quarterback Lamar Jackson has shown improvement as a passer, and he has more speed at wide receiver with the addition of first-round draft pick Marquise Brown, among others.

What still worries me, however, is how many rush attempts Coach John Harbaugh plans to allow for Jackson, who carried a heavy rushing load after becoming the starter last season. If Jackson gets between 150 and 200 carries, that will put him at a significant risk of injury.

The Raiders really need Antonio Brown on the field.

Coach Jon Gruden is playing to the cameras on HBO’s “Hard Knocks,” but the hits to his offense must really be weighing on him. Brown has only been a part of one practice after getting frostbite in a cryotherapy chamber and has been away from the team in a dispute over his 10-year-old helmet.

Additionally, Gabe Jackson, the team’s best guard, suffered a knee injury that will keep him out eight weeks.

The Raiders’ defense is a work in progress following an offseason of changes. If they are to be competitive, they will need to outscore teams — and that will be much harder to do without Brown in the lineup.

More NFL coverage:

A year ago, Freddie Kitchens was a position coach. Now he’s carrying Browns’ Super Bowl hopes.

John Clayton: The Cowboys’ Ezekiel Elliott problem is actually a Dak Prescott problem