San Francisco 49ers

Rampant injury bug spreads to Eric Reid, Aldon Smith ... and more

Colin Kaepernick scores on a 90-yard touchdown run against the San Diego Chargers during the third quarter on Saturday.
Colin Kaepernick scores on a 90-yard touchdown run against the San Diego Chargers during the third quarter on Saturday. The Associated Press

The 49ers’ season of attrition continued to take its toll as they lost another key defender, Eric Reid, Saturday against the Chargers.

Reid left the game in the first half with a concussion and was replaced by veteran Craig Dahl as the Chargers and quarterback Philip Rivers mounted a second-half comeback. Reid suffered two concussions as a rookie last season but did not miss a start.

Aldon Smith left the game in the fourth quarter with a head injury but returned in the overtime period. After being suspended for the first nine games of the season, he had two sacks in his second game back, Nov. 23 against Washington, but has not had any since.

The injury bug also bit further into the offense. One play, in fact, seemed to symbolize the 49ers’ rotten season.

When Colin Kaepernick fumbled late in the third quarter – and the ball was recovered in the end zone by San Diego – both of the team’s starting guards, Mike Iupati and Alex Boone, were left lying on the grass and had to be helped to the sideline. Both later returned to the field.

Receiver Michael Crabtree, meanwhile, started the contest but left in the first half due to a knee injury he had been nursing in the run-up to the contest. Crabtree, however, had to return late because fellow receiver Brandon Lloyd suffered a groin injury and Bruce Ellington pulled his hamstring.

The 49ers went into the game without receiver Stevie Johnson, who has missed the last two contests with a knee injury. The team has 20 players on injured reserve and other injury lists this year.

Davis returns – Right tackle Anthony Davis was in uniform for the first time since the Nov. 16 concussion he suffered against the Giants. Davis, who suffered the injury when his head hit the ground at the end of the Giants game, had been experiencing symptoms as recently as last week.

After starting every game since his rookie season in 2010, Davis dealt with a wave of issues this year beginning with a shoulder problem that required offseason surgery. He’s also suffered a hamstring strain, knee injury, ankle sprain and the concussion. Jonathan Martin has started nine games this season in Davis’ absence.

Draft dud – Joe Looney, who started at center last week and got an uncharacteristic rough review from offensive coordinator Greg Roman on Thursday, was inactive for Saturday’s game, the first time he has not been in uniform this season. Marcus Martin started the game at center.

Looney’s demotion is yet another blow to the 49ers’ infamous 2012 draft class, which began with receiver A.J. Jenkins and running back LaMichael James.

After James was released earlier this year, Looney became the lone remaining member of the 2012 class.

“He had a tough game,” Roman, who like Jim Harbaugh never criticizes a player, said of Looney’s performance against Seattle. “There were some things there that fundamentally he could have done better. You know, first start as a center, in that environment, against that crew which is pretty good, that’s tough duty. But I think he could have played better.”

Borland’s year ends – Chris Borland, who put himself into consideration to be the NFL’s defensive rookie of the year with a brilliant month of of November, became the 49ers’ third inside linebacker to go on injured reserve.

He suffered a severe ankle injury against the Seahawks last week and joins Patrick Willis (toe) and NaVorro Bowman (ACL) on the injury list.

No NFL player had more tackles than Borland since he took over Willis’ starting role in Week 7, and he was named the NFC’s rookie of the month of November. Second-year player Nick Moody made his first career start at inside linebacker.

Et cetera – Cornerback Perrish Cox grabbed his team-leading fifth interception of the season in the first quarter while Chris Culliver had his third of the year in the third quarter. Both starting cornerbacks are scheduled to become free agents in March.

▪  The 49ers filled Borland’s roster spot by promoting Chase Thomas from the practice squad, the eighth player the 49ers have called up from their developmental squad.

▪  With Ahmad Brooks out with a thumb injury, rookie Aaron Lynch started at left outside linebacker. The 49ers finished the game with two sacks, which were delivered by Dan Skuta and Quinton Dial.

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