The St. Louis Rams racked up 53 sacks last season, third in the NFL, with defensive end Robert Quinn getting 19 by himself.

Through four games, the Rams have one sack, and Quinn has been shut out.

Should be easy enough for the San Francisco 49ers to work on polishing up quarterback Colin Kaepernick's passing game, right?

Well ... the Rams do have the No. 1-ranked pass defense in the NFL, giving up 192.2 yards through the air per game, even if defensive end Chris Long was injured in the season opener and is on the injured reserve-designated to return list.

"Oh man, it's almost a setup, OK?," 49ers offensive coordinator Greg Roman said Friday. "Because when you watch the tape, I mean come on, they're this far away, the quarterback's getting rid of the ball or something happens or he just dishes it, it's just getting out of his hand. They're committing so many resources to 94 (Quinn) because 91 (Long) is not playing.

"But make no mistake about it -- we will not be lulled into that trap because all you've got to do is watch the film. Ninety-four is playing better than he did last year."

Even without a single sack?

"He's added to his repertoire," Roman said. "He has a great understanding of formations, what's around him, what he's going to do versus certain looks. When people try to double-team him he's got different answers, more answers.

"Physically he looks better than ever."

Niners left tackle Joe Staley figures to have his hands full with Quinn, then.

"Joe is one of the best tackles in the league, and he's constantly working every day to get better," Roman said. "From the first day of OTAs, he has been laser-like in his focus. It's been very impressive. He's been a great captain for us thus far."