SAN DIEGO -- There has been plenty of speculation this week that the 49ers could part ways with Colin Kaepernick and go into the season with rookie Jeff Driskel as the No. 2 quarterback behind Blaine Gabbert.
The argument against doing so? It came in the third quarter Thursday when Driskel relieved Kaepernick and then threw interceptions on his first two pass attempts. The second seemed particularly characteristic of a passer in need of NFL seasoning. Driskel was under pressure when he threw an off-balance pass to receiver Devon Cajuste in heavy coverage. The ball hung in the air and was grabbed by reserve cornerback Trevor Williams.
The 49ers must reduce their roster by 1 p.m. Saturday.
Driskel was 1-4 for three yards in three series against the Chargers before giving way to Christian Ponder at the end of the third quarter. Driskel, a sixth-round pick, finished the preseason 15-31 for 132 yards and a 33.3 passer rating. Ponder scored two rushing touchdowns and was solid through the air, too, finishing 8-14 for 101 yards. His passer rating for the preseason was 85.1, second only to Gabbert’s at 90.3.
Kaepernick nearly tossed an interception at the end of the half, but his throw in the end zone was dropped by safety Dexter McCoil. One play earlier he nearly had a touchdown on a nice pass to Ryan Whalen that carried the receiver just out of bounds. He finished the game 11-18 for 103 yards against the Chargers reserve defense. He also rushed four times for 38 yards. Kaepernick’s passer rating in two preseason games was 67.5.
Starting lineup revealed? -- None of the players expected to start the 49ers' Week 1 game against the Rams were on the field to begin Thursday's game.
That included several obvious absentees such as veterans Joe Staley and NaVorro Bowman as well as running back Carlos Hyde (concussion) and defensive lineman Quinton Dial (knee), both of whom are injured. Young players like first-round pick DeForest Buckner and cornerback Jimmie Ward also did not play.
The lineup also might have shed light on some position battles.
At inside linebacker, for instance, Ray-Ray Armstrong, Gerald Hodges and Michael Wilhote have been competing for the starting role next to Bowman. While Armstrong and Hodges watched from the sideline, Wilhoite -- a starter the last two seasons -- played the entire game next to Shayne Skov.
That signals that Hodges and Armstrong could share duties against the Rams, perhaps with Hodges lining up for running plays and Armstrong taking the field on obvious passing downs.
Meanwhile, veteran Zane Beadles and first-round draft pick Joshua Garnett have been sharing practice snaps with the first-team offense at left guard. Beadles, however, did not play in the game while Garnett played through the first half with the other 49ers' backup linemen. Garnett played 36 of the 49ers’ 78 offensive snaps.
Rush-ing the passer -- Outside linebacker Marcus Rush had two sacks in the second half Thursday, giving him six sacks in the last three games and more than any other player this preseason. Rush, a second-year player who is fighting for one of the spots at outside linebacker, also had an interception on a deflected pass in the fourth quarter.
“He had the couple of strip sacks in the Denver game, critical in the red area for us down there, and then came up again big today,” Chip Kelly said. “So, again, he’s a guy that you have to watch the tape and get a really good look at him because he’s really put himself into a spot where (if he) continues to make plays like that he’s going to be a good football player.”
Et cetera -- With Bruce Ellington (hamstring) out for the season, DeAndrew White handled punt returns in the game. Newcomer Jeremy Kerley also could be given that role this year.
* Wilhoite ended up leading the 49ers in preseason tackles with 22. Skov finished second with 19. Both logged more snaps than any other inside linebacker.
* Receiver DeAndre Smelter (hamstring) returned to practice earlier this week but was not at full speed. Smelter’s spot on the active roster is in question after he did not play at all in the preseason.