Anthony Davis didn't have the strongest start to his career as a first-round draft pick of the San Francisco 49ers in 2010. According to Pro Football Focus, he was the only offensive tackle with double-digit penalties, sacks allowed and quarterback hits allowed that season.
And then coach Jim Harbaugh arrived.
Davis has turned into a mauler in the 49ers' running game and has improved greatly in pass production -- and he was rewarded for his efforts Friday.
Davis signed a five-year, $37.295 million contract extension that will keep him under contract through 2019, a source told NFL.com's Albert Breer. The deal, which was first reported by ProFootballTalk, includes $17 million in total guarantees, according to Breer.
The 49erslater confirmed Davis' signing.
"Anthony is a very hardworking, dedicated and talented young player who has earned the respect of our entire organization," 49ers general manager Trent Baalke said in a statement. "Having already made significant strides early in his career, Anthony is just beginning to realize his full potential. We look forward to watching him achieve even greater results in the years to come."
It's the first of a few possible important extensions for the 49ers, with Colin Kaepernick, Michael Crabtree and Aldon Smith potentially coming in future years.
The 49ers' offensive line has enviable continuity in 2013, with all five starters and a few key backups returning. Guard Mike Iupati also figures to be a player that San Francisco wants to sign long-term because the running game remains the foundation of its offense.
Follow Gregg Rosenthal on Twitter @greggrosenthal.