Wide receiver Ladd McConkey is making such an impression with the Los Angeles Chargers that coach Jim Harbaugh says he’s “uncoverable” one on one and linebacker Daiyan Henley is still arguing about a catch the second-year pro made in workouts a month ago. McConkey is coming off a sensational season in which he set team rookie records with 82 catches and 1,149 yards receiving, while scoring seven touchdowns. Everyone is expecting more from McConkey — except for maybe Henley during their friendly practice rivalry — as he and quarterback Justin Herbert continue to develop the chemistry that has made them one of the NFL’s top pass-and-catch duos. Harbaugh, who brought the Chargers to their former hometown for two days of training camp practices this week, said fellow receiver Quentin Johnston and Ladd are “playing at an elite level.”