San Francisco cornerback Ambry Thomas broke his forearm Saturday in the 49ers preseason opener against the Titans. Coach Kyle Shanahan confirmed the news in his post-game press conference. He said Thomas will miss “some time” but it’s unclear how long he’ll be sidelined. “It will be some time. That’s all we have right now,” Shanahan said in post game. Thomas is a former Michigan Wolverine standout. The 49ers selected him in the third round of the 2021 NFL Draft. He has started 11 games and played in 42. This is a developing story with more details to come. The post 49ers cornerback Ambry Thoma…