he started the 49ers' season-opener against the carolina panthers and recorded two solo tackles in a 3–23 loss. on october 1, 2017, johnson collected eight combined tackles and a season-high two pass deflections during a 15–18 loss at the arizona cardinals. the next week, he earned a career-high nine combined tackles as the 49ers lost to the indianapolis colts 23–26. on december 24, 2017, johnson made his second career interception after picking off a pass attempt by blake bortles and returning it for a 50-yard touchdown during a 44-33 win over the jacksonville jaguars.