Barber: For 49ers, toughest test comes this week

SANTA CLARA - The 49ers just won the biggest game of the Shanahan era, beating a talented Browns team on “Monday Night Football.” And now they will play the new biggest game of the Shanahan era, an NFC West showdown against a squad that played in the Super Bowl last February.

Sunday represents a huge challenge but also an opportunity for the 49ers to prove their 4-0 record is not a façade. If they beat the Rams, who are 27-10 over the past two-plus seasons, it will be impossible for any reasonable person to dismiss their success.

More specifically, the next game is a litmus test for 49ers head coach Kyle Shanahan and his defensive coordinator, Robert Saleh. Both have received rave reviews this season. Both will be hard-pressed to keep the magic rolling against the Rams.

This matchup would have been an Xs-and-Os puzzle under any circumstances. But the current context puts the 49ers at a disadvantage. The most obvious reason: The Niners, coming out of the Monday night game, are operating on a short week. Meanwhile, the Rams have extra time to calculate. They last played on Thursday night, in a close loss to the Seahawks.

In other words, Los Angeles will have had nine days to prepare for the upcoming game, while San Francisco has five.

“I mean, it is what it is,” Shanahan said Wednesday, betraying a little smile that indicated I might be a dope for asking. “You always want more days, not just for a coach to prepare, but also for the players to rest.”

Having your opponent get the strategic jump on you is generally not ideal in the NFL, a league of detailed schematics, repetition and laser focus on one game at a time. It's especially dicey against the Rams, because of their celebrated brain trust, head coach and offensive play-caller Sean McVay and defensive coordinator Wade Phillips.

McVay, of course, is the coach every NFL team has been trying to clone for a couple years. He's still just 33 years old, and now has an NFC championship on his resume. His offense scored 527 points and gained 6,738 yards in the regular season last year, behind a quarterback, Jared Goff, who might be little better than average.

Granted, McVay's star has lost some luster. Los Angeles managed just three points against the Patriots in Super Bowl 53, and something weird is going on with star running back Todd Gurley, who has just 270 rushing yards through five games and is questionable for Sunday with a thigh bruise. Still, McVay's passing attack remains fairly lethal, and he has those extra days to study up on the 49ers.

The man responsible for shutting down the Rams offense is Saleh, the third-year defensive coordinator. Saleh has a good reputation in the league, having come from the Seattle system. His players love his energy and the uncomplicated nature of his defense. Before this year, though, Saleh didn't have the results to match.

That has changed in a hurry. The 49ers currently lead the NFL with 11 takeaways. They are second in total defense, second in passing yards allowed, fifth in rushing yards. They still haven't allowed a rushing touchdown. And just like that, Saleh's name is on the short list of prospective head coaching candidates for 2020. For example, Sports Illustrated's “Monday Morning Quarterback” column recently included him among “15 coordinators and position coaches to watch” - before Saleh's defense destroyed the Browns on Monday night.

“It's been really impressive just watching 'em,” McVay said on a Wednesday conference call. “They're taking the ball away, they're mixing in some different coverage principles. But there's a very clear, sound core philosophy they have that they're committed to. Guys having ownership of what they're trying to get done. And then I think situationally, he does an excellent job of having some game-plan things and some designers week by week that make it difficult.”

Saleh's defense is thriving through non-blitz pass pressure. If McVay is able to neutralize that rush to some extent, it will be interesting to see how Saleh reacts.

Shanahan's task may be even greater on Sunday, because his chess opponent is a legend. This is Wade Phillips' 28th season as a defensive coordinator. He will go down as one of the great assistant coaches in NFL history (and he was an underrated head coach, too). And he's the wrong man for the 49ers to be attacking this week.

That's because of the bad news Shanahan divulged Wednesday afternoon. Right tackle Mike McGlinchey has a knee injury, and is expected to miss four to six weeks. This absence is stacked upon that of left tackle Joe Staley, who is recovering from a fractured fibula. So the 49ers' starting tackles this weekend will be rookie Justin Skule, a sixth-round draft choice, and Daniel Brunskill, a former walk-on tight end at San Diego State who has been on the field for exactly eight NFL snaps.

These are the men who will be asked to block, for example, Michael Brockers and Dante Fowler on the edge while multiple teammates are trying to slow down the great Aaron Donald inside.

Oh, and another of the 49ers' best blockers, fullback Kyle Juszczyk, also is out with an injury.

But Shanahan's offense has been a revelation to watch this season. His pre-snap movement and post-snap misdirection has consistently resulted in wide-open receivers, and not always the one (tight end George Kittle) you'd expect. His running game has been all but unstoppable, no matter who is carrying the ball.

As I said, this is a huge challenge for both Shanahan and Saleh. But it's an opportunity, too. If Shanahan can out-scheme Phillips, he will have come of age as a play-caller. Ditto for Saleh in his mind games vs. McVay.

The 49ers' coaches have had bigger uphill climbs. But they simply didn't play a lot of meaningful games in 2017 and 2018. Their success has upped the stakes. This showdown with the Rams is important.

And you know what? I like the Niners' chances. The NFL may have figured out McVay a little bit. And while I'm on the board of directors of the Wade Phillips Fan Club, the man is 72 years old; this might not be his prime as a coordinator. It's Shanahan and Saleh who represent the future, and perhaps the present, of football strategy.

But they have to prove it. McVay got his team to the Super Bowl. Phillips won one of those, at Levi's Stadium incidentally, with the Broncos after the 2015 season. They own accomplishments that Shanahan and Saleh are chasing. To get there, those 49ers coaches must first prove they own the NFC West, and that route leads through Los Angeles.