TAMPA, Fla. — At times Sunday it looked like the Carolina Panthers brought their JV offense to south Florida. Because of a rash of injuries in the offensive backfield, the Panthers trotted out their fourth-team tailback, their quarterback of the future and a backup tailback who was with his third team in the span of a week.

And the young guys made a game of it. But in this season where little has gone right, the defense picked a bad day to have a bad day – and the Panthers headed home from Raymond James Stadium with another loss.

Tailback Carnell Williams converted a pair of key third-down plays on Tampa Bay’s final drive – including a 45-yard touchdown run with 2:42 remaining that sealed the Buccaneers’ 31-16 win.

It was Tampa Bay’s first sweep of Carolina since the Bucs’ Super Bowl season of 2002. The loss assured the Panthers (1-8) of their sixth non-winning season in John Fox’s nine years. “I think we’ve got guys that are fighting hard in a tough situation. I thought on offense, we showed improvement,” Fox said. “The results just weren’t quite what we were looking for.”

The day was not a total loss for the Panthers. With Buffalo’s win against Detroit, the Panthers pulled even with the Bills for the NFL’s worst record in the race for next year’s No. 1 pick.

In a sign of the Panthers’ offensive struggles this year, their first 100-yard rushing game was turned in by a down-the-depth-chart back – not DeAngelo Williams or Jonathan Stewart, who rushed for 1,100 yards apiece in 2009.

But with the top three tailbacks injured, Mike Goodson carried 23 times for 100 yards to become the first Carolina back to reach the century mark in his first start since Stewart ran for 120 in a 16-6 win against Tampa Bay last December.

Goodson’s day was not flawless: The second-year back lost a fumble on the Panthers’ first drive that Tampa Bay (6-3) turned into a touchdown – and the Bucs never trailed.

Panthers quarterback Jimmy Clausen, who reclaimed the starting job after Matt Moore’s season-ending shoulder injury, had a solid showing. The rookie from Notre Dame completed 16 of 29 passes for 191 yards, with no touchdowns and no interceptions.

The Panthers ran 62 plays – five more than the Bucs – but bogged down in scoring position. Carolina scored one touchdown in three red-zone opportunities – a 2-yard run by Josh Vaughan, who was cut by Indianapolis and had landed on Buffalo’s practice squad when the Panthers re-signed him.

Meanwhile, Tampa Bay came away with three touchdowns in four trips to the Panthers’ 20-yard line or inside. “When you’re in a close game like that, field goals aren’t going to win the game for you,” Clausen said. “You get down in the red zone, you need to put seven points on the board.”

The Panthers’ last possession exemplified their red-zone troubles. Inside the Bucs’ 1-yard line and out of timeouts with 28 seconds left, Clausen twice tried to sneak across the goal line – and was stuffed both times.

“That worked really well,” Fox said sarcastically. “On hindsight, I wish we had done something else. We were in a little bit of a time issue with no timeouts remaining, so you are a little limited. So we were not able to punch it in from two inches or whatever it was.”

It wouldn’t have changed the outcome. The Panthers’ fate was sealed when the defense couldn’t stop Tampa Bay on two third-and-long plays when it was still a one-score deficit. With the Panthers blitzing on third-and-15, Josh Freeman threw a screen pass to Williams, who darted 16 yards to the Bucs 45-yard line.

Carolina had another chance to get off the field. But on third-and-10 from the Panthers’ 45, Williams took a draw play through the heart of the defense for the put-away score.

The defense is showing signs of tiring after carrying the team the first part of the season. After allowing an average of 301.7 yards a game their first seven games, the Panthers have surrendered 400 yards in back-to-back games, including a season-high 421 to the Bucs.

“Some of those third downs killed us,” safety Charles Godfrey said. “I don’t think we played as good as we needed to play as a defense. We had a couple of mishaps here and there. We have to get back to playing the defense that we play. The offense picked it up a little bit.”

The Panthers couldn’t cover tight end Kellen Winslow, who caught all six balls thrown to him for 65 yards and a touchdown. In two games against the Panthers, Winslow has 10 catches for 148 yards.

Offensive coordinator Greg Olson said Tampa Bay’s running success – the Bucs averaged 6.2 yards a carry – helped open the play-action passes for Winslow.

Fox and others had a simpler theory: The 6-4, 240-pound Winslow is a matchup nightmare. While he was glad they converted them, Winslow said the Bucs have to avoid “those third-and-longs to beat the top-tier teams.”

Tampa Bay is not at the elite level, yet. But the NFL’s youngest team – a title the Bucs took from the Panthers by waiving a couple of veterans -- has come a long way from last year’s 3-13 finish.

Carolina veteran tackle Jordan Gross believes the Panthers can author a similar turnaround and make days like Sunday worthwhile.

“I hope I’m still here when this season pays off because it will at some point,” said Gross, who is signed through 2014. “You’re getting a tough, tough learning curve for a lot of young guys at a lot of positions, offensively and defensively. It’s going to eventually pay off, maybe by the end of this year … hopefully.”

jperson@charlotteobserver.com