With the Carolina Panthers spotty at best in terms of offensive production, the last team they might want to see on the schedule is the San Francisco 49ers.

The 49ers hold the NFL's top defense a month into the season, limiting opponents to 11.5 points per game.

The teams meet Sunday in Charlotte, N.C., where growing fan frustration with coach Matt Rhule tends to be one of the themes.

Yet it could be a tough turnaround for the 49ers (2-2), who topped the Los Angeles Rams 24-9 on Monday night and then must make a cross-country trip.

"Every week is a different game plan and a different opponent," 49ers coach Kyle Shanahan said.

For now, the Panthers (1-3) appear to have more problems.

"Nobody is happy where we're at, plain and simple," Panthers quarterback Baker Mayfield said. "It's time for our offense to actually play well instead of just relying on our defense and special teams to save us. ... There's plays to be made, but we have to make them. Let's get it fixed. It's time."

In quarterback ratings, Mayfield is 30th, while San Francisco's Jimmy Garoppolo is 14th.

It's that San Francisco defense that tends to stand out.

"They're excellent at what they do," Rhule said. "They've been great on defense for a long time."

The Panthers are last in the NFL in total offense with 262.3 yards per game.

"It's a great challenge for us," Mayfield said. "Their defense is playing at an extremely, extremely high level. We're looking forward to it. But it's one of those weeks that you've got to know what you're facing and own up to it."

The 49ers won't be lacking confidence on defense.

"I think it's best in the league," said San Francisco defensive end Nick Bosa, who leads the NFL with six sacks. "It's our mindset every year and this year we have the personnel to do it."

The 49ers could make tweaks. Safety Jimmie Ward (hamstring) and cornerback Jason Verrett (knee) were on the practice field Wednesday. Shanahan said it's possible they'll play at Carolina, and he said he wouldn't be hesitant to add them to the mix despite how well that unit has played so far.

"We'll see where we can fit him and how much he can handle," Shanahan said of Ward.

Among the 49ers who didn't practice Wednesday were defensive lineman Arik Armstead (foot, ankle) and offensive tackle Trent Williams (ankle).

The Panthers have received key contributions from their defense and that's a good thing. They've recorded a defensive touchdown in each of the last two games. They're the only team in the NFL with defensive touchdowns in two different games this season.

Another bonus for the Panthers has been kicker Eddy Pineiro, who's 8-for-8 on field goals. That includes a career-long 54-yarder last week.

This closes Carolina's three-game homestand. This will be a two-week trip for the 49ers, who'll remain in the Eastern time zone afterward because they play Oct. 16 at Atlanta.

The Panthers could be in a bind in the secondary, with safety Jeremy Chinn (hamstring) placed on injured reserve Wednesday. It's further complicated because safety Xavier Woods wasn't a participant in midweek practice because of hamstring ailment.

Carolina receiver Laviska Shenault also missed Wednesday's workout because of an injured hamstring.

The Panthers have won six of the last eight matchups with San Francisco, including three in a row at home in regular-season play. One of the 49ers' wins during the stretch came in the playoffs following the 2013 season.