Why the 49ers offense isn't relying on YAC this season

SANTA CLARA, Calif. -- Late in the fourth quarter of a Week 2 loss to the Los Angeles Rams, San Francisco 49ers wide receiver Brandon Aiyuk found himself running free for a potential game-winning touchdown.

With more than four minutes to play, a 52-yard touchdown would have sealed a 49ers' win. As quarterback Brock Purdy went through his progression, he saw Aiyuk, loaded up to throw it but decided against it.

After scrambling a bit, Purdy settled for a 5-yard completion to wideout Jauan Jennings. Purdy didn't throw it because the Rams busted a coverage, Aiyuk improvised as instructed and Purdy wasn't quite sure where the deep safety was as he prepared to let it fly.

Much was made of that missed opportunity but there's a bigger takeaway: it might be the only open deep ball Purdy turns down this year.

San Francisco's offense, long recognized as the home of yards after catch (YAC), continues to be one of the league's most efficient and productive units (red zone struggles aside). It just so happens to look different through six weeks this season than it has in the past.

The offense has seen an increased amount of man coverage and defenses dropping more defenders into coverage. As a result, Purdy has been forced to scramble more and throw deep into tight windows as defenses are crowding passing lanes and sending less rushers.

"I do feel like there may be a theme of man coverage and try to play one-on-one football," Purdy said. "We do see it more and more to get man. And so, for us, what does that mean? We've just got to beat the guy in front of us and then for me as a quarterback, I've got to be accurate with the ball and we've got to execute. That's football at its finest."

While six games isn't enough to determine if how the Niners are functioning offensively is more trend or a coincidence based on the opponent, it is, perhaps, not a surprise to see it happening more in the wake of the Super Bowl LVIII loss to the Kansas City Chiefs in February.

"The NFL is a complete copycat league, 100%," tight endGeorge Kittlesaid. "And when you have the Chiefs, they had success against us with man coverage. They did a really good job with that on us. And so teams are like, 'Hey, we're going to try it too until you can beat us.'... Not every team can do it because they don't have the guys to do it. But I've definitely seen more man coverage (this year)."

The Chiefs will face the 49ers again this weekend in a Super Bowl rematch (4:25 p.m. ET, Fox). When asked this week what the benefits are to playing so much man against the 49ers in particular, Chiefs defensive coordinator Steve Spagnuolo noted that the offense has been too good against the zone.

"I just think their system is built where they really can expose zone coverage and yet I think they've got enough skill that if you don't have the right people covering their men, that can be challenging too."

In the Super Bowl, the Chiefs played man coverage on 73.2% of drop backs, the second-most Purdy has faced since taking over as the starter in 2022, surpassed only by last season's loss to the Cleveland Browns. It was a more than 20% jump in man coverage from what Kansas City played in the regular season.

The man-heavy game plan allowed the Chiefs to congest the middle of the field with defenders, taking away some of the bread-and-butter throws the 49ers love. That gave Spagnuolo the opportunity to wait until the fourth-quarter to dial up blitzes from all angles.

"I thought last year was the best defense that we played all year," 49ers coach Kyle Shanahan said about the Chiefs defense. "And I feel that way this year so far... I've got a lot of respect for him and his scheme."

So far this season, 49ers' opponents (save for the Minnesota Vikings and Seattle Seahawks) have followed suit.

The 49ers have faced man coverage on 47.4% of their drop backs, up from the 41.8% they saw last season, and opponents have asked both outside cornerbacks to press at the line of scrimmage, the sixth-most in the league.

Making matters more difficult, Purdy and the 49ers have consistently seen seven or more defenders dropping into coverage. That includes a league-high 23 dropbacks in which three or fewer pass rushers have been sent at Purdy.

"They're very aware of our team and the threats that we have and I think they're just doing a really good job about playing really tight and getting two, three guys on every ball carrier," Kittle said.

There has been a significant decrease in YAC for a team that has ranked at or near the top of the league in every year since Shanahan took over in 2017. After finishing third in the NFL in YAC/completion in 2023 (6.4 yards), the 49ers have dipped to 30th in the league at 4.2 yards.

What that's done is create more opportunities for Purdy to either take off running (26 rushing attempts for 127 yards after finishing with 39 for 144 last season) or to hold the ball longer while moving around and looking for a big play to open up down the field.

"For me it's more been about keeping a play alive," Purdy said. "I'm not going into a game going, 'All right, I'm going to hold onto the ball longer here and try to make something happen.' It's how can I be efficient, help out the O-Line, get the ball out of my hands and do my job?"

That explains why Purdy spends the most time in the pocket (2.8 seconds), before throwing (3.17 seconds) and before getting sacked (5.93 seconds) of any qualified quarterback in the NFL. It's also why his 9.5 air yards per attempt also lead the league. All of those represent a major uptick from the 2.48 seconds in the pocket, 2.88 seconds before passing, 4.31 seconds to sack and 8.0 air yards/attempt from 2023.

It also puts more pressure on the offensive line to protect longer, something that would seem easier with fewer pass rushers to deal with but eventually proves difficult as Purdy moves around and vacates the pocket.

"There's just that hole, and ... watching a game, we're like, 'Yeah, it's three-man rush. It's going to take some time,'" offensive line coach Chris Foerster said. "And all of a sudden it's like, why is he still rushing and why is the ball not thrown?' That's what happens."

The absence of running back Christian McCaffrey(Achilles tendinitis) is a contributing factor. While Jordan Mason has filled in admirably in the run game, he also doesn't threaten defenses as much in terms of home-run speed or the passing game. McCaffrey averaged 4.2 catches per game last season, while Mason has eight receptions in six games.

"When Christian's out there, it's easier in everything you do," Shanahan said. "You know that defenses understand how good he is in one-on-ones, so you ... expect two people to be there, which helps you with other places."

Indeed, when teams paid a lot of attention to McCaffrey out of the backfield, it often opened up the middle of the field for Kittle and receivers Aiyuk, Jennings and Deebo Samuel Sr. to do damage.

Such openings have been harder to find. Niners' pass catchers are averaging just 2.83 yards of separation at the time the ball arrives, which is last in the league, and down from the 3.55 yards they averaged in 2023.

That has placed the onus on Purdy to fit more balls into tight windows, something he's tried to do at the highest rate in the league with 7.2 tight window attempts per game, double what he did last season.

Despite all of that, Purdy is still top five in the NFL in QBR (70.3), passing yards (1,629), yards per attempt (8.8) and completion percentage over expectation (5.2%). If Purdy continues to put up big numbers and McCaffrey returns, the 49ers will be harder to defend and can get back to the YAC.

"There's plays out there that we've had an opportunity to make YAC on," Kittle said. "We have individual guys that can play a little bit better and I think we're going to continue to play better, but I think it will open up... and we'll eventually get that back."