The Bee cited Brock's agent, Ron Slavin, as its source.
Brock - who broke his hand in Week 2 against the Dallas Cowboys and missed three weeks - started the season as the no. 3 cornerback for the Niners before his injury. Chris Culliver took advantage of Brock's missed time and filled the same role for the remainder of the season.
What cornerback Carlos Rogers decides to do will determine where on the depth chart Brock will find himself. If Rogers returns, he'd start training camp as the no. 4 corner. If Rogers leaves via free agency, Brock could find himself back in his old no. 3 spot behind Culliver and Tarell Brown.
Depth at the cornerback position will be paramount for the Niners with so many top of the line quarterbacks in the NFC, especially if Peyton Manning decides to join the party via the Arizona Cardinals.