The 32-year-old McCown was a third round pick (81st overall) out of Sam Houston State by the Arizona Cardinals in 2002. McCown spent four seasons with the Cardinals before spending 2006 with the Detroit Lions, 2007 with the Oakland Raiders, 2008 with the Miami Dolphins and Carolina Panthers, where he remained through the 2009 season, his most recent in the National Football League.
McCown spent 2010 with the now-defunct Hartford Colonials of the United Football League.
In 47 career games in the NFL, including 31 starts, McCown has completed 57.7 percent of 1,058 pass attempts for 6,584 yards with 35 touchdowns and 40 interceptions for a career passer rating of 71.3.
After releasing David Carr for salary cap purposes, the 49ers have been looking to add another veteran quarterback behind presumed starter Alex Smith and 2011 second-round draft choice Colin Kaepernick. Earlier this week, the 49ers worked out 34-year-old Daunte Culpepper, but did not sign the three-time Pro Bowler to a contract.