The 49ers' defense was a quarterback's worst nightmare last season. And that's being nice.
San Francisco allowed a measly, NFL-low 169.2 passing yards per game last season. Quarterbacks completed only 61.4 percent of their pass attempts against the 49ers and they were sacked 48 times, good for fifth in the league.
Richard Sherman locking down one side of the field certainly helps. As does Nick Bosa constantly putting pressure on QBs. But a key to the 49ers' defense also is the coverage ability of their linebackers at such young ages.
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SIGN UP HERE Pro Football Focus' website also actually has Greenlaw's overall coverage grade as 72.6 last season. The 2019 fifth-round pick stepped in for an injured Kwon Alexander -- who posted a 68.6 coverage grade across 423 snaps -- and came up clutch multiple times, especially against the 49ers' biggest rivals.
Warner is a tackling machine -- averaging 121 tackles per season through his first two years -- but he already is among the elite linebackers when it comes to breaking up passes. Warner had a 74.5 coverage grade across 1,166 total snaps last season. That was the fifth-best grade of any linebacker who played at least 1,000 snaps.
Through two seasons with the 49ers, Warner has three interceptions and 15 passes defensed.
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While Sherman rightfully grabs the spotlight by taking away top receivers, defenses have to be able to slow down tight ends and cover running backs out of the backfield. That's what makes Warner and Greenlaw so valuable.
There aren't many defenses with two linebackers like this.
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