The Los Angeles Chargers scored a big win in NFL free agency when they signed David Njoku ahead of the NFL schedule release.  Those Chargers already had breakout second-year player Oronde Gadsden on the roster and signed Charlie Kolar in free agency well before the move. Fixing a problematic-for-years area was a key goal of the offseason with offensive coordinator Mike McDaniel in town.  Seeing the calendar turn to May and still signing a former first-round pick and big-play artist like Njoku for Justin Herbert could be one of the steals of the offseason for any team.  And yet, some were quick to raise red flags about the Chargers’ big apparent win.  Chargers sign David Njoku in free agency…red flags raised David Njoku | Ken Blaze-Imagn Images Rest assured the Chargers knew some of the concerns around signing Njoku this late in the process.  Still, it’s an interesting topic amid the mostly overwhelming positivity.  NFL analyst Pat Thorman , for example, suggested that Njoku…