The earliest San Francisco can complete a trade of Smith is on March 12 after 4 p.m. ET, which is when the 2013 league year officially begins.
San Francisco has found a legitimate amount of interest, according to sources. The Kansas City Chiefs are interested and the Arizona Cardinals also are thought to be.
There is no deal in place right now, sources said.
Smith, the 2005 No. 1 overall draft pick, lost his starting job to Colin Kaepernick while sitting out with a concussion but was professional at every turn and continued to mentor his replacement.
For more on this story visit: Adam Schefter | ESPN