CHARLOTTE, N.C. – Carolina Panthers general manager Scott Fitterer spent the offseason trying to build a roster capable of challenging for a championship if he dropped the right quarterback into the mix like the Tampa Bay Buccaneers did with Tom Brady in 2020.

“I think we're a lot closer this year than we have been the last year or two,’’ Fitterer said during the offseason.

Defensively, it’s getting there.

Offensively, it’s not close.

If anything, it’s been a complete fail.

But getting there in the next couple of years may be more realistic after Thursday’s trade of running back Christian McCaffrey to the San Francisco 49ers that netted three 2023 draft picks (second-, third- and fourth-rounders) and one in 2024 (fifth round) to give Fitterer the maneuverability to draft a quarterback with a top pick next year.

“There’s a lot on defense to build with,’’ Fitterer said on Friday. “We’ve rebuilt the offensive line, which is the most important thing when you’re bringing in a young quarterback. ... We’re still building moving forward where we can drop that quarterback in and go.’’

In other words, the experiment to drop 2018 No. 1 overall pick Baker Mayfield into this year’s lineup didn’t work and the Panthers will likely focus on a strong 2023 quarterback draft class led by Kentucky’s Will Levis, Alabama’s Bryce Young and Ohio State’s C.J. Stroud to save the day.

To be clear, quarterback play hasn’t been the only problem during their 1-5 start, which makes this more of a rebuild than a simple fix. And beyond players, the Panthers likely will have to hire an entirely new coaching staff to replace Matt Rhule, who was fired, because interim coach Steve Wilks doesn’t have enough talented players to have the “incredible” showing owner David Tepper said he would want to see in order for Wilks to shed the "interim" tag.

Heading into Sunday’s game against the Buccaneers (1 p.m. ET, Fox), the rebuilt offensive line ranks 30th in pass block win rate and 28th in run block win rate, according to ESPN Stats & Information data.

And now they are without McCaffrey and wide receiver Robbie Anderson, who was traded to the Arizona Cardinals on Monday after being kicked out of Sunday’s 24-10 loss to the Los Angeles Rams by Wilks.

It's unlikely even someone like Brady, a future Hall of Famer with seven Super Bowl rings, would make Carolina a playoff contender with this roster. His current struggles with Tampa Bay (3-3), with the Bucs losers in three of their past four, show even he needs help.

“The short answer is no,’’ Hall of Fame NFL executive Bill Polian said of whether Carolina’s roster is close to being championship caliber with a good quarterback. “They’re a long way away.’’

Here are some reasons why:

The overall offense

Carolina ranks last in the NFL in total offense (260 YPG) and 28th in scoring (17.2 PPG). Even with McCaffrey healthy for all six games, the team’s 90.3 rushing yards per game is better than only six teams, including the last-place Bucs at 67.5 YPG.

Only three teams have fewer passing yards per game than Carolina’s 169.7.

Third down is a huge issue. Carolina ranks last in conversion rate at 23.6 and has run the fewest plays in the NFL with 323, or 53.8 per game.

“There’s a lot of pieces you would have to have in place to have what happened in Tampa occur, especially with a veteran quarterback,’’ Polian said, referring to the Bucs winning the Super Bowl in Brady's first season with the team.

Wide receivers

Carolina’s DJ Moore and Stefon Diggs of the Buffalo Bills are the only wide receivers to have at least 1,100 yards receiving the past three seasons.

Through six games this season, Diggs has 49 catches for 656 yards and 6 touchdowns.

Five Carolina receivers have a combined 47 catches for 635 yards and 3 touchdowns. Take Anderson’s 13 catches for 206 yards and 1 touchdown out of the mix, now that he's gone, and that drops to 44 catches for 430 yards and 2 touchdowns.

Moore has only 20 catches for 204 yards and 1 touchdown.

What appeared to be a strength entering the season is now a weakness.

“They have only one receiver in Moore that is a top flight guy,’’ Polian said.

Tight ends

Ian Thomas, known for his blocking, leads the Panthers with 10 catches on 16 targets for 115 yards and 0 touchdowns. That ranks 40th in the league.

Former head coach Matt Rhule, fired last week, believed 2021 third-round pick Tommy Tremble would eventually emerge, but he has only 5 catches for 42 yard and 0 touchdowns this season.

“He’s probably a [No. 2] at best,’’ Polian said of Tremble. “There’s nobody like the guy that [quarterback] Cam [Newton] had in [tight end] Greg Olsen, which is important for a young guy, or a small guy like Mayfield.’’

Newton and Olsen were one of the best quarterback-tight end combinations in the NFL between Newton’s rookie season in 2011 and 2016. Olsen averaged 71 catches, 897.3 yards and 5.3 touchdowns during that time.

Brady had Rob Gronkowski during his 2020 Super Bowl run. Gronkowski had 45 catches for 623 yards and seven touchdowns. Tampa Bay tight ends had 11 touchdown catches that season.

Another missing piece.

The offensive line

Beyond the statistics mentioned above, Polian never believed Ikem Ekwonu was a true left tackle when the Panthers made him the No. 6 overall of the 2022 draft.

“The line is better than last year, but I worry about Ickey as a left tackle,’’ Polian said. “He’s a phenomenal guard and maybe a right tackle, but I don’t know if he’s a left tackle.’’

Quarterback

The quarterbacks Carolina dropped into the lineup this season have failed. Mayfield had a 15.5 Total QBR through the first five games before being sidelined with an ankle injury that will keep him out again on Sunday. He’s headed for career worsts in almost every statistical category.

PJ Walker, who will make his second straight start this week and will keep the job if he excels, didn’t fare any better the past Sunday. He completed 10 of 16 pass attempts for 60 yards, giving him a Total QBR of 5.6.

“Things haven’t happened and jelled as quickly as we’d like them to,’’ offensive coordinator Ben McAdoo said. “That’s quite obvious. But I'm not discouraged.’’

Finances

On the plus side, the Panthers have 20 of 22 starters under contract for next season. Quarterback and defensive tackle Matt Ioannidis are the only exceptions.

But considering Carolina is 1-5 with those starters, that’s not a big plus. The Panthers also aren’t expected to have a lot of salary cap room in 2023 to sign big-time free agents without cutting some of their own, although clearing McCaffrey’s 2023 cap hit of $19,550,750 helped.

According to Spotrac data before the trade, they ranked 26th in the NFL in estimated cap space with minus-$4,708,627.

Samir Suleiman, the vice president of football administration, told the team website this week there’s a plan in place. He conservatively projected more than $80 million in cap space in 2024 and $145 million in 2025.

But that’s two years away, and fans already are impatient with this season's start following four straight losing seasons.

Will 2023 draft help?

The picks Carolina got for McCaffrey will go a long way toward building for the future. Beyond those, they have four more in 2023 (first-, second-, fourth- and fifth-rounders) and six in 2024 (one each in the first six rounds).

Their 2023 first-rounder may end up being a top-three pick and likely will have to be used on a quarterback, since Mayfield and Sam Darnold are in the last year of their respective contracts and neither has performed well enough to get a new deal.

Fortunately for Carolina, this is a strong class of quarterbacks. But with young quarterbacks there are usually growing pains. It took Newton three years to have a winning season after Carolina selected him No. 1 overall in 2011. Buffalo’s Josh Allen was 5-6 in his first season (2018) before making the Bills a perennial playoff contender in his second season.

Then there are those like Carolina’s Mayfield and Darnold -- the first and third overall picks, respectively -- of the 2018 draft. Mayfield has only one winning season, 11-5 in 2020, and Darnold has none.

So to drop a rookie into the mix likely wouldn’t be a quick fix, either.