Leading the way is quarterback Alex Smith, who hasn't thrown an interception in a franchise-record 185 consecutive regular-season passes. Smith threw just five picks last season the fewest in the league for a regular starter as San Francisco committed a NFL-low 10 turnovers.
The 49ers have not committed a regular-season turnover since Smith's second-quarter interception against the Baltimore Ravens on Thanksgiving night last year.
They have not lost a fumble since tight end Vernon Davis fumbled after catching a pass from Smith in the fourth quarter of a Nov. 6 victory at Washington. The 49ers have a streak of 36 consecutive quarters without losing a fumble.
Smith doesn't downplay the significance of turnover-free play in San Francisco's return to NFL prominence.
"In the history of the NFL, the strongest correlation to winning and losing is the turnover ratio," Smith said. "The turnover battle is the No. 1."
The 49ers know all about it. They finished 13-3 last season and made their first trip to the playoffs since 2002 after leading the NFL with a plus-28 turnover differential, one of the league's best since the 1970 AFL-NFL merger.
The previous seven seasons, all of which they finished without a winning record, San Francisco committed 221 turnovers and had a cumulative turnover differential of minus-57.
The 49ers changed that dramatically once Jim Harbaugh and a new coaching staff took over the team last year. San Francisco matched the NFL record for fewest turnovers in a season, also held by the 2010 Patriots.
"Ball security relates to your team being successful, and we're very serious about that," Harbaugh said.
The 49ers make a "commitment to taking care of the ball," Harbaugh said, and Smith was transformed by that approach last season.
In his first six NFL seasons, Smith threw 53 interceptions and lost 16 fumbles while throwing 51 touchdown passes. He threw 17 touchdown passes last season, when Smith set a team record for fewest picks in a season, and he lost just two fumbles.
Smith has been most impressive keeping the ball out of the hands of opposing defenders when he goes to the air. He completed 20 of 26 passes without an interception during last week's 30-22 victory at Green Bay, breaking Hall of Famer Steve Young's previous team record of 184 consecutive passes without a pick.
Including San Francisco's two playoff games last season, Smith has now thrown 253 consecutive passes without an interception.
"That's huge, and it's a credit to Alex," offensive coordinator Greg Roman said. "He's got an innate feel for risk management on the fly. A lot of that goes unseen, but it's all calculated by him. He's done an incredible job."
Smith isn't the only one. Three-time Pro Bowl running back Frank Gore, who had two lost fumbles among his 299 touches last season, enters Sunday's game with a career-best string of 226 touches (220 rushes, six receptions) without a lost fumble.
Gore's backup, Kendall Hunter, has never fumbled in his 17 career games. Gore and Hunter combined for 153 yards rushing on 25 carries last week against the Packers.
Harbaugh credits running backs coach Tom Rathman, who played fullback for the 49ers from 1986-1993, with "doing as good a job as any of us have ever seen done," in preparing his unit to protect the football.
"There's no secret to it. We preach it, but we don't preach it to the point of suffocating people," Roman said. "But everybody understands what we're trying to get done.
"We emphasize ball security, how the defense tries to strip the ball, and do all the different things to educate the players on what's coming at them. Anybody that handles the football understands that they've got the collective fate of the team in their hands. If you have the ball, it's your job to protect it. It's that simple."
The 49ers also are getting some help in that regard from their own aggressive defense, which tied for the NFL lead last year with 38 takeaways.
Coaches have instituted "Takeaway Thursdays" each week in practice, where San Francisco's defense stresses stripping the ball and picking off passes from the team's first-string offense.
"It's something that starts on the practice field, and that's where we get it," Smith said. "It starts there, and then carry it over to the field."
League levies fines
Safeties Madieu Williams of Washington, Taylor Mays of Cincinnati and Rahim Moore of Denver have been fined $21,000 each by the NFL for unnecessary roughness in Week 1.
Williams made helmet-to-helmet contact with Jimmy Graham when the Saints tight end was defenseless with about three minutes remaining in Sunday's game at New Orleans. Mays did the same to Baltimore tight end Ed Dickson in a Monday night game. Rahim unnecessarily struck defenseless Steelers receiver Emmanuel Sanders in the head and neck area Sunday night.
Houston DE Antonio Smith says he's been fined $21,000 for kicking Miami guard Richie Incognito, who was not disciplined.
Drawing $15,750 fines were Minnesota defensive end Everson Griffen for helmet-to-helmet contact with Jacksonville quarterback Blaine Gabbert, and Dallas tackle Tyron Smith for a horse collar tackle. Vikings DT Letroy Guion was fined $7,875 for roughing Gabbert.
Kansas City running back Shaun Draughn was fined $7,875 for unnecessary roughness against Atlanta, while Miami center Mike Pouncey drew the same amount for the same act against Houston.
Around the league
Jets • All-Pro cornerback Darrelle Revis has been ruled out for New York's game at Pittsburgh on Sunday with a concussion. Coach Rex Ryan says Revis was cleared for non-contact practice for the first time Friday, but will not play against the Steelers. Revis was injured in the season opener last Sunday against Buffalo when teammate Bart Scott accidentally kicked him in the head.
Dolphins • Running back Daniel Thomas has been ruled out of Sunday's game against Oakland because of a concussion, leaving the team with little experience behind starter Reggie Bush. Thomas was hurt in Sunday's loss at Houston. Rookie Lamar Miller, a fourth-round draft pick from the University of Miami, will likely be active for the first time.
Chargers • San Diego plans to retire Junior Seau's No. 55 before hosting the Tennessee Titans (0-1) on Sunday. No. 55 will join Lance Alworth's No. 19 and Dan Fouts' No. 14 as the only retired numbers in the team's 53-year history. Seau, the hard-hitting, fist-pumping emotional leader of the Chargers for 13 of his 20 NFL seasons, committed suicide on May 2.
Week 2 schedule
Green Bay 23, Chicago 10
Tampa Bay at N.Y. Giants, 11 a.m.
New Orleans at Carolina, 11 a.m.
Arizona at New England, 11 a.m., Ch. 13
Minnesota at Indianapolis, 11 a.m.
Baltimore at Philadelphia, 11 a.m., Ch. 2
Kansas City at Buffalo, 11 a.m.
Cleveland at Cincinnati, 11 a.m.
Houston at Jacksonville, 11 a.m.
Oakland at Miami, 11 a.m.
Dallas at Seattle, 2:05 p.m.
Washington at St. Louis, 2:05 p.m.
Tennessee at San Diego, 2:25 p.m.
N.Y. Jets at Pittsburgh, 2:25 p.m., Ch. 2
Detroit at San Francisco, 6:20 p.m., Ch. 5
Denver at Atlanta, 6:30 p.m., ESPN