Back in 2020, San Francisco 49ers defensive coordinator Robert Saleh had to figure out early how he was going to manage life without standout defensive end Nick Bosa, whose torn ACL in Week 2 cast an ominous shadow on what turned into a dreadful season.
Now, only three weeks into 2025, Saleh's second stint with the Niners is going to have to accomplish the exact same thing. Bosa is again going to miss the rest of the year with a torn ACL, one suffered in the Week 3 victory over the Arizona Cardinals.
True, San Francisco spent considerable effort last offseason giving Saleh more tools, including a trade for veteran edge Bryce Huff and using a first-round draft pick on defensive end Mykel Williams.
But, at least historically speaking, Bosa's presence has been crucial for the 49ers, both when Saleh has been in the coaching ranks and when he hasn't.
Judging by that criteria alone, the Niners may be poised again for another difficult season with their best pass-rusher sidelined.
49ers are night and day when Nick Bosa is on the field
Bosa's 2020 ACL tear provided the greatest sample size of how well (or poorly) San Francisco performed as a team without him in the lineup. And, while it's important to also acknowledge how banged up the 49ers were that season elsewhere, it's still shocking to see the difference in wins and losses between when he's suited up and when he hasn't.
As the San Francisco Chronicle's Eric Branch pointed out, the Niners are 57-28 in games with Bosa playing, compared to 6-12 when he's been absent.
Digging deeper, because there was visible evidence of his absence in the win over Arizona, Niners Nation's Kyle Posey pointed out how quarterback Kyler Murray was under significantly less pressure following Bosa's injury and had substantially more time to throw, over a half a second:
The 49ers pressure rate with Nick Bosa on the field yesterday: 45.5%
— Kyle Posey (@KP_Show) September 22, 2025
The 49ers pressure rate with Nick Bosa off the field yesterday: 28%
Kyler Murray's average time to throw was 0.51 seconds longer without Bosa on the field
A Bosa-less defense had a pressure rate of just 28 percent, while Saleh's group managed a 45.5-percent pressure rate before the injury.
That's glaring. And it's certainly going to be an issue for San Francisco's defense for the rest of the season, barring some sort of incredible breakouts from either Huff or Williams. Or, potentially, a blockbuster trade to help make up for Bosa's absence.
Until then, it's a blunt truth to admit the 49ers are far less a team entering Week 4 than they were a week ago prior to the All-Pro's devastating injury.
And it'll be up to Saleh to again figure out how to manage it.