"I was always confident," he told reporters Thursday. "I never lost any confidence at all."
Johnson struggled to start the season, laying a 4-yard egg against the New England Patriots in Week 1, and he gained fewer than 25 yards on the ground in four of his first five games this season. He has turned it around in recent weeks, gaining more than 90 rushing yards in each of past last four games. He also has shown some of the explosiveness that made him one of the NFL's most dynamic players, with runs of 80 yards or more in two of his past three contests.
Johnson signed a four-year, $53.5 million contract before last season, and his up-and-down performances have led to questions about his drive, but he believes his recent play should quiet the doubters.
"I am sure I answered some questions," Johnson said. "Earlier, a lot of people thought I just wasn't playing hard or just got the big deal and gave up or lost a couple of steps or things like that. If you've been paying attention, you know all of those are false."
Follow Kevin Patra on Twitter @kpatra.