SAN FRANCISCO (AP) — Jim Harbaugh wanted tight end Delanie Walker to play a bit more than the rest of San Francisco's starters in the final preseason game considering a bum knee limited him during training camp.
Walker caught a 32-yard touchdown pass from backup quarterback Colin Kaepernick, Alex Smith handed off five times before calling it a night and the 49ers wrapped up the preseason with a 35-3 win over the San Diego Chargers on Thursday.
Walker returned to action for the first time since the exhibition opener after he injured his right knee during practice on Aug. 12. He missed time late last season with a broken left jaw before returning for the NFC championship, so the TD catch will only serve as a boost heading into the regular season next weekend.
"I missed two preseason games, so just the opportunity to go out there and play, I took advantage of it, and I had a great time," Walker said. "I wanted to get my feet back under me, make sure the knee was good. I felt like everything was perfect and had a great game."
Philip Rivers went 8 for 10 for 89 yards and an interception in one quarter for San Diego (3-1), which will be back in the Bay Area to open the season on Monday Night Football Sept. 10 at Oakland.
Harbaugh hollered at the replacement officials when they didn't initially call intentional grounding on Rivers' left-handed throw under pressure with 3:10 remaining in the first quarter. Neither considered it a big deal afterward.
Kaepernick connected with rookie first-round draft pick A.J. Jenkins on a 12-yard score midway through the second quarter that put the defending NFC West champion ahead 21-0. Kaepernick finished 12 for 18 for 158 yards and two touchdowns for the 49ers (3-1).
"Tonight was the first time I really felt like I just went out there and let it loose and just played ball," Kaepernick said. "It felt good to finally get in a rhythm."
Smith didn't throw a pass in his short outing, handing the ball to Kendall Hunter on the first four plays of the game and one more to Jenkins. Anthony Dixon ran for a 1-yard TD.
"Just wanted him to go out and break a sweat," Harbaugh said.
San Francisco defensive coordinator Vic Fangio called out his unit's struggles — particularly the backups — in a 29-24 win at Denver on Sunday night in which the Niners fell behind 17-0 in the first quarter before rallying in the second half to win. This time, the 49ers starters got the night off completely on a windy, chilly summer evening along the bay at Candlestick Park.
Not that San Diego did enough right on offense to give the No. 2 D much of a test.
San Francisco's Josh Johnson, fighting for the No. 3 quarterback job with 2011 holdover Scott Tolzien, threw a 51-yard touchdown pass to Nathan Palmer in the third quarter and another late in the period to Garrett Celek for 3 yards.