Anquan Boldin has been in the NFL since 2003, caught 772 passes, has gone to three Pro Bowls and played in two Super Bowls, so he isn't exactly an under-the-radar kind of player.Yet Sports Illustrated's Peter King, in his Monday Morning Quarterback column this week, says Boldin's impact on the 49ers may be the most overlooked storyline of NFL training camps so far.Why?Because King, a longtime NFL observer, believes Boldin's impact on the Niners will be enormous, both as a receiver and as a leader, especially in light of what is likely to be the season-ending Achilles' tendon injury by No. 1 receiver Michael Crabtree."Boldin, traded for a pittance (the 199th pick in the April draft) could be the most important receiver on two different Super Bowl contenders, just months apart," wrote King of the ex-Ravens standout. "And nobody's talking about it. It's the NFL story hiding in plain sight."Boldin, 32, remains fit, strong and fast and is coming off a 2012 regular season in which he caught 65 passes for 921 yards and four TDs, then added 22 postseason receptions for 380 yards and four more scores for Baltimore, which beat the 49ers in the Super Bowl.He's a good route runner who battles...