49ers activate linebacker Aldon Smith

San Francisco 49ers All-Pro linebacker Aldon Smith was activated to the 53-man roster from the non-football injury list Thursday, two days after he turned himself in to Santa Clara County authorities as he faces weapons charges.

Smith had been undergoing rehabilitation at an in-patient facility for substance abuse since late September and missed five games. With San Francisco (6-2) on its bye this week, Smith could resume practicing and working out on his own, then formally practice next week ahead of a Nov. 10 home game against the Carolina Panthers.

Smith was charged Oct. 9 with three felony counts of illegal possession of an assault weapon, stemming from a party at his home in June 2012.

49ers Coach Jim Harbaugh said on his weekly radio show that Smith met with 49ers officials Wednesday at team headquarters. General Manager Trent Baalke said last week in London that Smith would have to show “progress” to play again this year.

Smith will be due in court twice — Nov. 12 and Nov. 19 — to face DUI and weapons charges.

Meriweather apologizes

Brandon Meriweather issued an apology by proxy Thursday, with the head of the NFL players’ union releasing a statement saying that the Washington Redskins safety is “sorry” over comments made about targeting opponents’ knees.

“I spoke to Brandon,” NFLPA Executive Director DeMaurice Smith said in the statement. “He is passionate about the game, and I know he is sorry for what he said. He is concentrating on helping his team win the rest of the season. Brandon knows that all players have a responsibility to each other and to play within the rules of the game.”

Meriweather has been sanctioned twice by the league this season for illegal hits targeting the helmet and neck of defenseless receivers. He returned Monday from a one-game suspension and said from now on he’ll have “to take people’s knees out” and cause career-ending injuries.

“You’ve got to tear people’s ACLs and mess up people’s knees now,” he said Monday. “You can’t hit ‘em high anymore.”

Bills’ QB is ‘50-50’

Buffalo Bills quarterback Thad Lewis missed his second straight practice Thursday and remains questionable for Sunday’s game against the Kansas City Chiefs.

Bills Coach Doug Marrone reiterated Lewis has a “50-50” chance of playing after bruising his ribs in Sunday’s loss to New Orleans.

If Lewis is unable to play, the Bills will start undrafted rookie Jeff Tuel or newly signed free agent Matt Flynn against the unbeaten Chiefs.