The 49ers are working on a contract extension for tight end Vernon Davis, according to sources.
San Francisco has already given linebacker Patrick Willis a lucrative extension this offseason.
Two sources have told CSN Bay Area of the team's desire to lock up Davis, who had a breakout season in 2009.
The tight end is asking for a five-year, $40 million contract with $25 million in guaranteed money.
49ers, Davis Working On Extension