SAN FRANCISCO The 49ers started Monday's game without starting receiver Braylon Edwards, then lost his replacement, Ted Ginn, to an ankle injury early in the third quarter.
With Ginn out of the game, Kyle Williams saw more snaps at receiver and he also handled punt returns he had two fair catches for the 49ers. Williams finished the game with four catches for 33 yards, two of the receptions coming on key third-down plays in the first half.
"Whenever a guy goes down, you have to be able to fill in," Williams said. "There are still opportunities to be had out there. We got it done as a whole team and everybody pitched in.
Ginn's injury also gave seldom-used wideout Brett Swain a chance to play. Swain entered the game on offense for the first time this season, and he finished with one catch for nine yards in the fourth quarter.
Edwards was on the 49ers' injury report this week with a knee injury, but he practiced on a limited basis Thursday through Saturday.
Asked why Edwards didn't play, Jim Harbaugh said he and his coaches thought they would be better off with Michael Crabtree, Ginn and Williams in the receiver rotation.
It was the second time in two weeks the team was without Edwards, the team's marquee free-agent signing this summer on offense. Edwards suffered a meniscus tear in the second game of the season and has not been the same since the injury.
He returned to the lineup on Oct. 30 but was held out on Dec. 4 to rest the knee. After that game, Edwards insisted the knee felt better and that he was eager to play again. "I don't plan on watching any more clinching going on without me," he said at the time.
He started the following game in Arizona but played only a handful of snaps. Furthermore, he and quarterback Alex Smith continued to be off kilter. Smith threw in Edwards' direction twice, and both passes were incomplete.
Edwards has 14 catches for 172 yards this season and is still looking for his first touchdown with the 49ers.
Records fall David Akers's 38-yard field goal in the second quarter was his 141st point of the season. That broke Jerry Rice's single-season scoring franchise scoring record (138 points), which Rice set in 1987.
Meanwhile, first-round draft pick Aldon Smith corralled Ben Roethlisberger for two and half sacks, giving him 13 on the season. That's one more than Charles Haley had as a rookie in 1986. The NFL record for rookie sacks is 14 ½, which was set by Tennessee's Javon Kearse in 1999.
Et cetera The 49ers limited Steelers starting running back Rashard Mendenhall to 64 rushing yards meaning the defense now has now held the opposing rusher to less than 100 yards in 36 straight contests. The 49ers also became the first team in history to play their first 14 games without allowing a rushing touchdown.
* Left tackle Joe Staley, who suffered a concussion last week, left the game in the fourth quarter with a leg injury. Like last week, he was replaced by Alex Boone.
* Cornerback Shawntae Spencer has leapfrogged Tramaine Brock on the team's depth chart. Spencer played while Brock was inactive. Rookie guard Daniel Kilgore was active for the first time all season, and he got into the game in the fourth quarter.