San Francisco 49ers linebacker NaVorro Bowman agreed to a five-year extension Tuesday that runs through the 2018 season. The team didn't disclose the terms of the deal, but an NFL.com report said it was worth $45.25 million, $25.5 million of which was guaranteed. "NaVorro epitomizes what we look for in a 49er," 49ers general manager Trent Baalke said in a statement. "We're excited that the All Pro tandem of [Patrick] Willis and Bowman will be together in red and gold for years to come." Including Ahmad Brooks and Aldon Smith, the 49ers now have all four of their starting linebackers under contract through at least the 2015 season. The 49ers took Bowman, 24, in the third round of the 2010 Draft. He has recorded 337 tackles, four sacks and three fumble recoveries in three years, including a team-leading 129 tackles this season.