Once a seven-point favorite in their game against the Jacksonville Jaguars on Sunday, the Los Angeles Chargers are now favored by just 3.5 points at BetMGM. The sharp drop in the spread is a strong indication that quarterback Justin Herbert is likely to miss Sunday’s game after suffering a fracture to his rib cartilage in last Thursday’s game against the Chiefs. The change to the spread comes as Herbert was reportedly sidelined for at least the start of Chargers practice on Friday. According to ESPN’s Lindsey Thiry, Herbert didn’t throw a single pass for the 19 minutes that practice was…