CB Richard Crawford flashes for Chargers in loss to 49ers

Philip Rivers, Melvin Gordon and most of the starters did not play for the San Diego Chargers in the team's final preseason game on the road at Levi's Stadium. Here are some quick thoughts on the Chargers' 14-12 loss to the 49ers:

QB depth chart: With Rivers watching from the sideline for the second time in three games, reserve quarterback Kellen Clemens played the entire first half. The University of Oregon product failed to lead a scoring drive, finishing 10-of-17 for 64 yards, no touchdowns and no interceptions. Brad Sorensen put up decent numbers, finishing with 15 of 22 for 154 yards, with one touchdown pass and one interception.

Crawford makes plays, gives up plays: Chargers cornerback Richard Crawford finished with a 29-yard interception return for a touchdown and a sack. But he also gave up a 70-yard touchdown to Bruce Ellington, and a 16-yard touchdown to Buster Anderson in the final quarter.

Chargers still can't run the football: San Diego finished with just 16 rushing yards in the first half and 42 for the game. The Chargers came into Thursday's contest averaging 3.4 yards a contest, No. 19 in the NFL.

San Diego offense sputters: Veteran punter Mike Scifres got a workout, punting 10 times as the Chargers couldn't get anything going on offense. The Chargers finished with just 250 total yards on offense.

A player who looks amazing: Running back Donald Brown flashed speed and made some plays in the passing game for the Chargers and looks poised to have a bounce-back year, after struggling in his first season with the Chargers last year. Brown finished with five catches for 34 yards, and did a nice job in pass protection for San Diego.

Rookie watch: Undrafted rookie free agent Tyrell Williams had been impressive during training camp, but had two critical drops that would have moved the chains. However, Williams finished with a 63-yard touchdown for a score. He's likely a practice squad candidate at this point. Chi Chi Ariguzo, an undrafted rookie free agent out of Northwestern, led the Chargers with seven combined tackles and half a sack.

Carrethers active: Nose tackle Ryan Carrethers played stout against the run and was active in pursuit, finishing with four combined tackles. Carrethers led all San Diego defensive linemen with nine tackles during exhibition play.

Injury update: Ariguzo suffered an apparent right shoulder injury with a little over five minutes left and had to be helped off of the field by San Diego's training staff.