SAN FRANCISCO Vernon Davis, who played all but two snaps against the Packers in Week 1, missed chunks of two first-half drives after getting poked in the eye by defensive end Cliff Avril.
On the play before his eye injury, Davis and fellow tight end Delanie Walker tangled with Avril near the 49ers' sideline, with all three of them going down in a heap.
Davis said he hoped that Avril wasn't retaliating for that play.
"No hard feelings," Davis said. "You take it. You come out with wounds and bruises, but you bounce back. You go in the next day, you get treatment for those things, and mentally, you get prepared for the next game."
Avril was involved in scrapes throughout the game, most of them with 49ers right tackle Anthony Davis, who feuded with Avril both during and after via Twitter last year's game in Detroit.
Vernon Davis returned later in the half and seemed to show no ill effects.
He scored the 49ers' first touchdown of the game and their last, 23-yard reception with 3:04 left in the game.
Unhappy returns Ted Ginn's replacements have a tough time in Candlestick Park.
In the 49ers' first meaningful home game since Kyle Williams gave away two punt returns in the NFC Championship Game, another Ginn substitute, Kendall Hunter, coughed up the ball on a kickoff return.
The Lions recovered the first-quarter miscue at the San Francisco 25-yard line, and four plays later Jason Hanson booted home a 41-yard field goal.
The fumble ended a 26-quarter streak in which the 49ers did not commit a turnover in the regular season. It also was the first lost fumble by the 49ers in a regular-season game since Davis' during a Nov. 6 game against the Redskins last year.
The fumble also was another indication that the 49ers special-teams units the league's finest a year ago still are developing.
They allowed a punt return for a touchdown during preseason and another last week against the Packers. The 49ers complained the touchdown in Green Bay should have been called back for an illegal block.
Ginn has missed the first two games of the season with a sprained ankle.
Clutch play Williams had no miscues in his first meaningful home game since the NFC Championship Game.
In fact, he made one of the clutch plays, sprinting back to recover a rolling kick by the Lions after they had cut the 49ers' lead to eight points late in the game. The 49ers were expecting an onside kick, and Detroit instead kicked it downfield.
Williams also returned one punt for eight yards.
Et cetera Before the game, punter Andy Lee and kicker David Akers were presented with golden-boot trophies as winners of the 2011 Golden Toe Award given by Pro Football Weekly.
Quarterback Scott Tolzien was active for the first time in his career as an emergency backup to Lee as a holder for field goals and extra points. Lee injured his right hand last week in Green Bay trying to make a tackle.
Top draft picks A.J. Jenkins and LaMichael James were inactive for the game. The only draft pick who suited up was sixth-rounder Trenton Robinson, a safety.
Among the 49ers' sideline attendees were actors Vince Vaughn and Owen Wilson, who also took pictures with the team inside the locker room after the game. The longtime collaborators are shooting a movie, "The Internship," in San Francisco.