Johnston (groin) is listed as questionable for Sunday's game at Kansas City due to a groin injury, Eric Smith of the Chargers' official site reports.
Johnston showed up on the Chargers' Week 15 practice report Friday as a limited participant, and his status thus is up in the air heading into the weekend. Sudden appearances on practice reports are typically indicative of health concerns suffered during drills, but in any case, the team will confirm Johnston's availability about 90 minutes before Sunday's 1 p.m. ET kickoff.