By STEVE REED

AP Sports Writer

CHARLOTTE — No NFL quarterback has struggled quite as much this season as Carolina’s Baker Mayfield.

The bumpy road isn’t expected to get any smoother today for the 2018 No. 1 overall draft pick.

Mayfield, who is last in the NFL in ESPN’s total quarterback rating, leads the league’s worst offense against its top-ranked defense when the Panthers (1-3) host the San Francisco 49ers (2-2).

Mayfield joined the Panthers in July after a trade with the Cleveland Browns. He has struggled mightily, completing a league-low 54.7% of his passes while being limited to 186.7 yards passing per game with four touchdowns and three interceptions.

“I pride myself on being a guy that elevates the guys around him and being able to lead at an extremely high level,” Mayfield said. “And obviously, that has not happened yet.”

Panthers offensive coordinator Ben McAdoo said he deserves blame too, adding that he needs to put his players in better position to make plays and find ways to get Christian McCaffrey and D.J. Moore the ball more often.

That’s easier said than done against the 49ers.

San Francisco has been dominant defensively with Nick Bosa’s NFL-best six sacks leading a fearsome pass rush and playmaking safety Talanoa Hufanga anchoring the back end. The Niners have given up only 37 points to opposing offenses — tied for the second fewest through four games since 2010 — and have allowed 3.81 yards per play, the lowest mark through four games since 2008.

Panthers coach Matt Rhule said “I think they’re number one in every category.”

“I think it’s to be best in the league,” Bosa said about the expectations of San Francisco’s defense. “It’s kind of our mindset every year and this year we have the personnel to do it. Not that we haven’t in the past, but at all three levels are elite players.”

JIMMY G VS. BAKER

When the Panthers were considering making a move at quarterback this past offseason, they pursued trades for Deshaun Watson, Jimmy Garoppolo and Mayfield.

Watson wound up in Cleveland and talks with the 49ers about Garoppolo never really got off the ground because of the money involved in taking him on.

Now they’ll face Garoppolo on Sunday.

“Jimmy, he’s won a lot of games there and got them to the NFC championship last year,” Panthers defensive coordinator Phil Snow said. “He just wins games.”

TIPPED BALLS

The 6-foot-1 Mayfield continues to struggle with batted balls at the line of scrimmage. He’s had an NFL-high 11 this season, including five last week by Arizona — one of which was intercepted and led to a Cardinals touchdown.

McAdoo said the Panthers have worked extensively on the problem this week in practice

“It’s a copycat league,” McAdoo said. “So what you are seeing is teams are rushing and then once they feel that they are blocked or stymied (on the pass rush), they will put their hands up and jump.”

SAN FRANCISCO (2-2) at CAROLINA (1-3)

Sunday, 4:05 p.m., CBS

OPENING LINE: 49ers by 6 1/2, according to FanDuel SportsBook.

AGAINST THE SPREAD: San Francisco 2-2, Carolina 1-3.

SERIES RECORD: Panthers lead 13-9.

LAST MEETING: 49ers beat Panthers 51-13 on Nov. 27, 2019, at San Francisco.

LAST WEEK: 49ers beat Rams 24-9; Panthers lost to Cardinals 26-16.

49ERS OFFENSE: OVERALL (24), RUSH (9), PASS (12), SCORING (t-27).

49ERS DEFENSE: OVERALL (t-1), RUSH (2), PASS (2), SCORING (1).

PANTHERS OFFENSE: OVERALL (32), RUSH (24), PASS (31), SCORING (17).

PANTHERS DEFENSE: OVERALL (18), RUSH (25), PASS (12), SCORING (t-13).

TURNOVER DIFFERENTIAL: 49ers plus-1; Panthers minus-2.

49ERS PLAYER TO WATCH: DE Nick Bosa had two sacks and 14 quarterback pressures last week, according to PFF. He leads the NFL with six sacks and is one of three players to have at least one sack in every game. The most recent player to have at least one sack in the first five games was Clay Matthews in 2019. The 49ers had seven sacks last week of the Los Angeles Rams’ Matthew Stafford.

PANTHERS PLAYER TO WATCH: D.J. Moore. Panthers coach Matt Rhule said the team needs to make a concerted effort to get Moore more involved in the offense this week. After having three straight seasons with at least 1,150 yards receiving, Moore has just 138 yards on 13 receptions through four games.

KEY MATCHUP: Panthers QB Baker Mayfield vs. 49ers defense. Mayfield has had an NFL-high 11 passes batted at the line of scrimmage. Opposing rushers are purposely looking to get their hands up and disrupt passing lanes, making it difficult for the 6-foot-1 Mayfield to see his receivers.

KEY INJURIES: The Niners are on their third-string LT after All-Pro Trent Williams went down with a high ankle sprain in Week 3 and Colton McKivitz hurt his knee last week. Jaylon Moore is expected to get the nod. … DT Arik Armstead is dealing with a foot injury that sidelined him in Week 3 and forced him to leave last week’s game early. … DT Javon Kinlaw (knee) sat out last week but could be active this week. … The Panthers will be without S Jeremy Chinn, one of their top defenders and leading tacklers, because of a hamstring injury. …WR Laviska Shenault’s status is uncertain after he injured his hamstring in Week 4.

SERIES NOTES: The Panthers came into the league as an expansion team in 1995 and initially played in the NFC West with the 49ers. San Francisco was their first rival. … The Panthers have won six of the past eight matchups.

STATS AND STUFF: San Francisco will stay East after this game and practice in West Virginia before playing at Atlanta next week. … The 49ers are allowing 3.81 yards per play, the fewest through four games since 2008. … The Niners defense has allowed only 37 points this season, tied for the second fewest through four games since 2010. Only the 2019 Patriots allowed fewer with 14. … The Niners haven’t allowed a first-half TD all season. … San Francisco has forced a league-high 18 three-and-outs and is tied for second with 15 sacks, including seven last week. … The 49ers are tied for the fewest three-and-outs on offense with four. … San Francisco DE Samson Ebukam had his third career multi-sack game last week. … Niners LB Dre Greenlaw had a career-high 15 tackles last week. … The Niners are 0-2 on the road. They were the third-best road team the past three seasons with an 18-7 mark. … This is Carolina’s third straight home game. … The Panthers have lost 10 of their past 11 games. … The Panthers have lost eight of their past nine home games. … Carolina is last in the league in third down rate, converting just 25.5% of its attempts. … RB Christian McCaffrey has two 100-yard rushing games and two games where he’s been held to fewer than 35 yards rushing. … DE Frankie Luvu had a 33-yard interception return for a touchdown against the Cardinals after a forced fumble that led to a touchdown return the week before against the Saints. … K Eddy Pineiro is 8 of 8 on field-goal attempts since joining the Panthers. … Panthers P Johnny Hekker completed a pass off a fake punt last week, but the first down was nullified because of an illegal man downfield.

FANTASY TIP: Niners WR Deebo Samuel had 101 yards after the catch last week, his fourth game with at least 100 yards after the catch since entering the league in 2019 — the most by any wide receiver.

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