San Francisco 49ers linebacker Kwon Alexander returned to the practice field on Thursday for the first time since tearing his pectoral muscle midway through the season.Alexander’s return opens a three-week window in which he can be activated from injured reserve.San Francisco coach Kyle Shanahan told reporters earlier in the week that Alexander’s potential return is more likely for the NFC Championship Game on Jan. 19, as opposed to the team’s first playoff game in the divisional round set for Jan. 11.The 49ers (13-3) earned a first-round bye after capturing the top seed in the NFC playoffs.”He’s coming along,” Shanahan said. “There’s definitely going to be a chance. I don’t think that will be this week, but if we’re fortunate enough to win our first game, I think he could have a chance after that. We’re still holding out hope for that, but we’ll see how it goes over these next couple weeks.”Alexander sustained the injury in the 49ers’ 28-25 victory over the Arizona Cardinals on Oct. 31. He went on injured reserve Nov. 5.Alexander, 25, recorded 34 tackles, one forced fumble, one interception and a half-sack in eight games this season, his first in San Francisco after signing a four-year, $54 million contract.Alexander has collected 414 tackles, 7.5 sacks, seven interceptions, seven forced fumbles and two fumble recoveries in 54 career games with the Tampa Bay Buccaneers and 49ers. He was a Pro Bowl selection with the Buccaneers in 2017.