Los Angeles Chargers head coach Jim Harbaugh just gave an injury update on quarterback Justin Herbert ahead of the team’s Week 4 matchup against the Kansas City Chiefs. While speaking to reporters on Wednesday, Harbaugh said that Herbert is out of the walking boot and could do some things in practice. Harbaugh also said that the Pro Bowl quarterback is “progressing” from his high ankle sprain. Herbert underwent an MRI on his ankle on Monday. He injured the ankle before the Week 2 game and aggravated the injury in Week 3 missing the final 10 snaps. During training camp, the former Oregon QB mis…