Tramaine Brock has signed a four-year contract extension with the San Francisco 49ers.

The new deal will keep the cornerback with the NFC West side until the end of the 2017 NFL season.

General manager Trent Baalke told the team's website: "Tramaine is a great example of what hard work and dedication can lead to.

"He has taken advantage of his opportunities since signing with our team as an undrafted free agent in 2010 and has certainly earned this extension.

"Extending the contracts of our young and talented players has always been, and will continue to be, one of our primary goals."

Brock has made 18 tackles and four interceptions for the 49ers so for this season.