Jimmy Garoppolo wasn't the San Francisco 49ers starting quarterback when the season began.

Andy Dalton wasn't the New Orleans Saints starting quarterback when the season began.

But both quarterbacks have settled into starting positions as the 49ers and Saints prepare to meet Sunday afternoon in San Francisco.

Garoppolo was backing up Trey Lance until Lance suffered a season-ending fractured ankle in the second game of the season. Garoppolo has started the past eight games and helped lead San Francisco (6-4) to three consecutive victories and a tie with Seattle atop the NFC West.

He completed 20 of 29 passes for 228 yards with four touchdowns and no interceptions in a 38-10 victory over Arizona on Monday night in Mexico City.

"He is such a talented quarterback," said running back Christian McCaffrey, who caught seven passes from Garoppolo for 67 yards and ran for 39 yards on seven carries against the Cardinals. "He is a great leader, super smart, can make any throw and just a great guy to be around. It's been a lot of fun to be able to pick his brain and mesh with him."

The 49ers' surge has come since the acquisition of McCaffrey in a trade with Carolina to join an offense that already featured Deebo Samuel, Brandon Aiyuk and George Kittle.

San Francisco leads the NFL in total defense (283.9 yards per game) and is fourth in scoring defense (17.3 points per game). The 49ers are allowing the fewest rushing yards per game (81.1) and the fewest yards per rush (3.4).

"It's very rare when you look at the tape that there's one person in the screen," coach Kyle Shanahan said. "It's almost every play that there are 11 people on the screen. They're playing well together."

The Saints offense has been inconsistent this season. Starting quarterback Jameis Winston was injured during a season-opening win at Atlanta, then battled through losses to Tampa Bay and Carolina before Dalton took over.

New Orleans (4-7) won just two of Dalton's first seven starts and head coach Dennis Allen considered returning to Winston after Dalton threw two interceptions in a 20-10 loss at Pittsburgh two weeks ago.

But Allen stayed with Dalton, who had one of the most efficient performances of his career last week. Dalton completed 21 of 25 passes for 260 yards with three touchdowns and no interceptions in a 27-20 home victory against the Los Angeles Rams.

"The way we played last week, we were able to get the ball out of my hand quickly and guys were getting open at the right time," Dalton said. "We executed really well from that standpoint. It just comes down to playing in rhythm and playing on time."

The Saints have yet to win consecutive games this season, but they sit in third place in the NFC South, just two games behind first-place Tampa Bay in the loss column.

New Orleans has seen an inordinate number of key players sidelined by injury this season, but the participation report Wednesday showed progress.

Five starters who had been sidelined returned on a limited basis -- cornerback Marshon Lattimore (abdomen), defensive ends Cameron Jordan (eye) and Marcus Davenport (calf), tackle James Hurst (concussion) and guard Andrus Peat (triceps).

"When you get guys back out there, everybody gets a lift," Allen said.

The 49ers had just four players on their injury report, including Samuels (hamstring), who was limited.